Dr. Vijay K. Varadan Profile

Dr. Vijay K. Varadan

Professor of Eng.Sci & Neurosurgery

SPIE Involvement:

Conference Program Committee | Author | Editor | Instructor

Publications (292)

Proceedings Article | 26 March 2021 Presentation

Wearable and mobile healthcare nanosystems and their applications in medicine

Vijay Varadan

Proceedings Volume 11590, 1159003 (2021) https://doi.org/10.1117/12.2584159

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Proceedings Article | 24 April 2017 Presentation + Paper

3D printing of wearable fractal-based sensor systems for neurocardiology and healthcare

Mouli Ramasamy, Vijay Varadan

Proceedings Volume 10167, 1016709 (2017) https://doi.org/10.1117/12.2261386

KEYWORDS: Electrodes, 3D printing, Additive manufacturing, Fractal analysis, Sensors, Medicine, Heart, Skin, Brain, Electrocardiography

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Proceedings Article | 24 April 2017 Paper

Wearable nanosensor systems and their applications in healthcare

Mouli Ramasamy, Prashanth Kumar, Vijay Varadan

Proceedings Volume 10167, 1016703 (2017) https://doi.org/10.1117/12.2264812

KEYWORDS: Skin, Sensing systems, Temperature sensors, Telecommunications, Sensors, Medicine, Nanosensors, Surgery, Electronics, Wireless communications

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Proceedings Article | 24 April 2017 Presentation + Paper

Nanomechanics of carbon nanotubes

Mouli Ramasamy, Prashanth Kumar, Vijay Varadan

Proceedings Volume 10167, 101671O (2017) https://doi.org/10.1117/12.2264368

KEYWORDS: Graphene, Polymers, Single walled carbon nanotubes, Tissues, Sensors, Mechanics, Carbon nanotubes, Composites, Diagnostics, Regenerative medicine

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Proceedings Article | 24 April 2017 Presentation + Paper

Study of heart-brain interactions through EEG, ECG, and emotions

Mouli Ramasamy, Vijay Varadan

Proceedings Volume 10167, 101670I (2017) https://doi.org/10.1117/12.2264371

KEYWORDS: Nervous system, Neurons, Control systems, Autoregressive models, Electroencephalography, Brain, Cognition, Electrocardiography, Heart, Neuroscience

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Proceedings Article | 24 April 2017 Presentation + Paper

SAW based micro- and acousto-fluidics in biomedicine

Mouli Ramasamy, Vijay Varadan

Proceedings Volume 10167, 101671D (2017) https://doi.org/10.1117/12.2264370

KEYWORDS: Proteins, Diffusion, Nanolithography, Magnetism, Directed self assembly, Thermodynamics, Microfluidics, Molecules, Molecular assembly, Molecular self-assembly

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Proceedings Article | 24 April 2017 Presentation + Paper

Left lateral decubitus position on patients with atrial fibrillation and congestive heart failure

Vijay Varadan, Prashanth Kumar, Mouli Ramasamy

Proceedings Volume 10167, 1016705 (2017) https://doi.org/10.1117/12.2260646

KEYWORDS: Heart, Atrial fibrillation, Electrocardiography, Nervous system, Blood, Injuries, Lung, Cell death, Resistance, Failure analysis

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Proceedings Article | 24 April 2017 Presentation + Paper

Atrial fibrillation and sudden cardiac death: catheter-based sensor and mapping system of the heart

Mouli Ramasamy, Prashanth Kumar, Vijay Varadan

Proceedings Volume 10167, 1016706 (2017) https://doi.org/10.1117/12.2260778

KEYWORDS: Heart, Atrial fibrillation, Single crystal X-ray diffraction, Electrodes, Tissues, Imaging systems, Electrocardiography, Sensors, Computing systems, 3D displays

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Proceedings Article | 24 April 2017 Presentation + Paper

Magnetic nanotubes for drug delivery

Mouli Ramasamy, Prashanth Kumar, Vijay Varadan

Proceedings Volume 10167, 1016715 (2017) https://doi.org/10.1117/12.2264367

KEYWORDS: Hematite, Neurons, Absorbance, Polymers, Calibration, Spectroscopy, Nanocomposites, Microwave radiation, Absorption, Magnetism

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Proceedings Article | 21 July 2016 Paper

Study of emotion-based neurocardiology through wearable systems

Mouli Ramasamy, Vijay Varadan

Proceedings Volume 9802, 98021A (2016) https://doi.org/10.1117/12.2219525

KEYWORDS: Heart, Brain, Nervous system, Electroencephalography, Electrocardiography, Cognition, Neuroscience, Neurons, Control systems, Autoregressive models

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Proceedings Article | 21 July 2016 Paper

Wireless nanosensor system for diagnosis of sleep disorders

Mouli Ramasamy, Vijay Varadan

Proceedings Volume 9802, 98021F (2016) https://doi.org/10.1117/12.2219621

KEYWORDS: Receivers, Amplifiers, Sensors, Transmitters, Electrodes, Polysomnography, Chest, Data communications, Skin, Nanosensors

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Proceedings Article | 15 July 2016 Paper

Differential diagnosis of cardiovascular diseases and T-wave alternans

Mouli Ramasamy, Vijay Varadan

Proceedings Volume 9802, 98021E (2016) https://doi.org/10.1117/12.2219620

KEYWORDS: Heart, Lead, Single crystal X-ray diffraction, Electrocardiography, Blood, Ions, Diagnostics, Potassium, Arteries, Statistical analysis

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Proceedings Article | 15 July 2016 Paper

Real-time monitoring of drowsiness through wireless nanosensor systems

Mouli Ramasamy, Vijay Varadan

Proceedings Volume 9802, 98021G (2016) https://doi.org/10.1117/12.2219511

KEYWORDS: Signal processing, Signal detection, Electroencephalography, Cameras, Eye, Head, Nanosensors, Sensors, Electromyography, Electrocardiography

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Proceedings Article | 15 July 2016 Paper

3D printing of nano- and micro-structures

Mouli Ramasamy, Vijay Varadan

Proceedings Volume 9802, 98020H (2016) https://doi.org/10.1117/12.2224069

KEYWORDS: 3D printing, Electrodes, Additive manufacturing, Skin, Printing, Microfluidics, Sensors, Inkjet technology, 3D microstructuring, Wave propagation

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Proceedings Article | 15 July 2016 Paper

Wearable nanosensor system for monitoring mild traumatic brain injuries in football players

Mouli Ramasamy, Vijay Varadan

Proceedings Volume 9802, 980218 (2016) https://doi.org/10.1117/12.2219516

KEYWORDS: Electroencephalography, Brain, Nanosensors, Traumatic brain injury, Injuries, Electronics, Transmitters, Receivers, Data conversion, Head

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Proceedings Article | 3 April 2015 Paper

Wireless nanosensors for monitoring concussion of football players

Mouli Ramasamy, Robert Harbaugh, Vijay Varadan

Proceedings Volume 9434, 943408 (2015) https://doi.org/10.1117/12.2177285

KEYWORDS: Electroencephalography, Brain, Nanosensors, Traumatic brain injury, Injuries, Electronics, Head, Transmitters, Receivers, Sensors

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Proceedings Article | 3 April 2015 Paper

Nanosensor system for monitoring brain activity and drowsiness

Mouli Ramasamy, Vijay Varadan, Robert Harbaugh

Proceedings Volume 9434, 94340A (2015) https://doi.org/10.1117/12.2177286

KEYWORDS: Signal processing, Electroencephalography, Electrodes, Signal detection, Receivers, Head, Linear filtering, Global system for mobile communications, Nanosensors, Sensors

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Proceedings Article | 3 April 2015 Paper

Study of nanosensor systems for hypertension associated cerebrovascular and cardiovascular disorders

Mouli Ramasamy, Vijay Varadan

Proceedings Volume 9434, 94340R (2015) https://doi.org/10.1117/12.2190840

KEYWORDS: Blood pressure, Nanosensors, Heart, Light emitting diodes, Arteries, Cardiovascular disorders, Sensors, Electrocardiography, Plasmonics, Nanotechnology

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Proceedings Article | 30 April 2014 Paper

Neural activity based biofeedback therapy for Autism spectrum disorder through wearable wireless textile EEG monitoring system

Ahna Sahi, Pratyush Rai, Sechang Oh, Mouli Ramasamy, Robert Harbaugh, Vijay Varadan

Proceedings Volume 9060, 90600D (2014) https://doi.org/10.1117/12.2045530

KEYWORDS: Electroencephalography, Electrodes, Brain, Amplifiers, Neurons, Mirrors, Sensors, Computing systems, Data acquisition, Oxygen

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Proceedings Article | 16 April 2014 Paper

Efficient RF energy harvesting by using a fractal structured rectenna system

Sechang Oh, Mouli Ramasamy, Vijay Varadan

Proceedings Volume 9060, 90601B (2014) https://doi.org/10.1117/12.2045182

KEYWORDS: Antennas, Fractal analysis, Energy harvesting, Linear filtering, Telecommunications, Autoregressive models, Medicine, Nanotechnology, Electronic components, Resistors

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Proceedings Article | 16 April 2014 Paper

Efficient heart beat detection using embedded system electronics

Mouli Ramasamy, Sechang Oh, Vijay Varadan

Proceedings Volume 9060, 90600K (2014) https://doi.org/10.1117/12.2044881

KEYWORDS: Signal processing, Electrocardiography, Heart, Microcontrollers, Electronics, Embedded systems, Medicine, Receivers, Electrodes, Sensors

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Proceedings Article | 16 April 2014 Paper

Wireless sleep monitoring headband to identify sleep and track fatigue

Mouli Ramasamy, Sechang Oh, Vijay Varadan

Proceedings Volume 9060, 90600E (2014) https://doi.org/10.1117/12.2045173

KEYWORDS: Signal processing, Electroencephalography, Signal detection, Receivers, Sensors, Amplifiers, Head, Linear filtering, Data communications, Global system for mobile communications

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Proceedings Article | 16 April 2014 Paper

Yttrium oxide based three dimensional metamaterials for visible light cloaking

Pratyush Rai, Prashanth Kumar, Vijay Varadan, Paul Ruffin, Christina Brantley, Eugene Edwards

Proceedings Volume 9060, 90601D (2014) https://doi.org/10.1117/12.2045216

KEYWORDS: Refractive index, Metamaterials, Oxides, Yttrium, Visible radiation, Dielectrics, Metals, Waveguides, Electromagnetism, Fabrication

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Proceedings Article | 16 April 2013 Paper

Development of thermoelectric inks for the fabrication of printable thermoelectric generators used in mobile wearable health monitoring systems

Jungmin Lee, Hyun Jung Kim, Linfeng Chen, Sang Choi, Gyanesh Mathur, Vijay Varadan

Proceedings Volume 8691, 86910R (2013) https://doi.org/10.1117/12.2009765

KEYWORDS: Thermoelectric materials, Printing, Body temperature, Fabrication, Energy harvesting, Nanoparticles, Composites, Bismuth, Scanning electron microscopy, Tellurium

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Proceedings Article | 16 April 2013 Paper

Synthesis and electrochemical properties of spinel lithium manganese oxides for lithium ion batteries

Gaojun Wang, Linfeng Chen, Gyanesh Mathur, Vijay Varadan

Proceedings Volume 8691, 869113 (2013) https://doi.org/10.1117/12.2010063

KEYWORDS: Lithium, Spinel, Manganese, Oxides, Ions, Sol-gels, Solid state physics, Particles, Prototyping, Nanoparticles

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Proceedings Article | 16 April 2013 Paper

Study of the electrochemical properties of magnetite, maghemite and hematite nanoparticles for their applications in lithium ion batteries

Linfeng Chen, Gaojun Wang, Jining Xie, Pratyush Rai, Jungmin Lee, Gyanesh Mathur, Vijay Varadan

Proceedings Volume 8691, 869115 (2013) https://doi.org/10.1117/12.2010070

KEYWORDS: Nanoparticles, Hematite, Oxides, Iron, Prototyping, Lithium, Ions, Magnetism, Scanning electron microscopy, Crystals

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Proceedings Article | 9 April 2013 Paper

Wireless health monitoring helmet for football players to diagnose concussion and track fatigue

Sechang Oh, Prashanth Shyam Kumar, Hyeokjun Kwon, Pratyush Rai, Mouli Ramasamy, Vijay Varadan

Proceedings Volume 8691, 869106 (2013) https://doi.org/10.1117/12.2009719

KEYWORDS: Sensors, Electroencephalography, Electrodes, Diagnostics, Amplifiers, Linear filtering, Oxygen, Transmitters, Oximeters, Light emitting diodes

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Proceedings Article | 9 April 2013 Paper

Motion artifact removal algorithm by ICA for e-bra: a women ECG measurement system

Hyeokjun Kwon, Sechang Oh, Vijay Varadan

Proceedings Volume 8691, 86910A (2013) https://doi.org/10.1117/12.2009681

KEYWORDS: Electrocardiography, Independent component analysis, Interference (communication), Signal detection, Algorithm development, Detection theory, Computer simulations, Motion measurement, Algorithms, Chemical vapor deposition

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Proceedings Article | 9 April 2013 Paper

Smart real-time cardiac diagnostic sensor systems for football players and soldiers under intense physical training

Prashanth Kumar, Sechang Oh, Hyeokjun Kwon, Pratyush Rai, Vijay Varadan

Proceedings Volume 8691, 869108 (2013) https://doi.org/10.1117/12.2009861

KEYWORDS: Electrocardiography, Lead, Single crystal X-ray diffraction, Sensors, Scanning electron microscopy, Electrodes, Diagnostics, Medicine, Amplifiers, Autoregressive models

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Proceedings Article | 24 October 2012 Paper

Wireless glucose monitoring watch enabled by an implantable self-sustaining glucose sensor system

Pratyush Rai, Vijay Varadan

Proceedings Volume 8548, 85481G (2012) https://doi.org/10.1117/12.946334

KEYWORDS: Glucose, Sensors, Electrodes, Blood, Oxygen, Diffusion, Carbon, Carbon nanotubes, In vitro testing, Oxidation

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Proceedings Article | 24 October 2012 Paper

Printable thermoelectric devices and conductive patterns for medical applications

Jungmin Lee, Hyunjung Kim, Linfeng Chen, Sang Choi, Vijay Varadan

Proceedings Volume 8548, 85481C (2012) https://doi.org/10.1117/12.946254

KEYWORDS: Thermoelectric materials, Printing, Point-of-care devices, Manufacturing, Signal detection, Bismuth, Neodymium, Composites, Fabrication, Medical devices

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Proceedings Article | 24 October 2012 Paper

Synthesis of iron oxide nanotubes and their applications in neuroscience and drug delivery

Linfeng Chen, Jining Xie, Kiran Aatre, Justin Yancey, Malathi Srivatsan, Vijay Varadan

Proceedings Volume 8548, 854867 (2012) https://doi.org/10.1117/12.946051

KEYWORDS: Hematite, Iron, Magnetism, Oxides, Absorbance, Scanning electron microscopy, Neuroscience, Neurons, Transmission electron microscopy, Calibration

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Proceedings Article | 24 October 2012 Paper

Nanocomposite electrodes for smartphone enabled healthcare garments: e-bra and smart vest

Prashanth Kumar, Pratyush Rai, Sechang Oh, Hyeokjun Kwon, Vijay Varadan

Proceedings Volume 8548, 85481O (2012) https://doi.org/10.1117/12.946029

KEYWORDS: Electrodes, Electrocardiography, Medicine, Absorption, Nanocomposites, Skin, Manufacturing, Silver, Bioalcohols, Sensors

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Proceedings Article | 24 October 2012 Paper

E-Bra system for women ECG measurement with GPRS communication, Nanosensor, and motion artifact remove algorithm

Hyeokjun Kwon, Sechang Oh, Prashanth Kumar, Vijay Varadan

Proceedings Volume 8548, 85482N (2012) https://doi.org/10.1117/12.946121

KEYWORDS: Electrocardiography, General packet radio service, Telecommunications, Ions, Chemical vapor deposition, Electrodes, Heart, Signal detection, Neodymium, Gold

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CardioVascular Disease(CVD)s lead the sudden cardiac death due to irregular phenomenon of the cardiac signal by the abnormal case of blood vessel and cardiac structure. For last two decades, cardiac disease research for man is under active discussion. As a result, the death rate by cardiac disease in men has been falling gradually compared with relatively increasing the women death rate due to CVD[2]. The main reason of this phenomenon causes the lack a sense of the seriousness to female CVD and different symptom of female CVD compared with the symptoms of male CVD. Usually, because the women CVD accompanies with ordinary symptoms unrecognizing the heart abnormality signal such as unusual fatigue, sleep disturbances, shortness of breath, anxiety, chest discomfort, and indigestion dyspepsia, most women CVD patients do not realize that these symptoms are related to the CVD symptoms. Therefore, periodic ECG signal observation is required for women cardiac disease patients. ElectroCardioGram(ECG) detection, treadmill test/exercise ECG, nuclear scan, coronary angiography, and intracoronary ultrasound are used to diagnose abnormality of heart. Among the medical checkup methods for CVDs checkup, it is very effective method for the diagnosis of cardiac disease and the early detection of heart abnormality to monitor ECG periodically. This paper suggests the effective ECG monitoring system for woman by attaching the system on woman’s brassiere by using augmented chest lead attachment method. The suggested system in this paper consists of ECG signal transmission system and a server program to display and analyze the transmitted ECG. The ECG signal transmission system consists of three parts such as ECG physical signal detection part with two electrodes made by gold nanowire structure, data acquisition with AD converter, and data transmission part with GPRS(General Packet Radio Service) communication. Usually, to detect human bio signal, Ag/AgCl or gold cup electrodes are used with conductive gel. However, the gel can be dried when taking long time monitoring. The gold nanowire structure electrodes without consideration of uncomfortable usage of gel are attached on beneath the chest position of a brassiere, and the electrodes convert the physical ECG signal to voltage potential signal. The voltage potential ECG signal is converted to digital signal by AD converter included in microprocessor. The converted ECG signal by AD converter is saved on every 1 sec period in the internal RAM in microprocessor. For transmission of the saved data in the internal RAM to a server computer locating at remote area, the system uses the GPRS communication technology, which can develop the wide area network(WAP) without any gateway and repeater. In addition, the transmission system is operated on client mode of GPRS communication. The remote server is installed a program including the functions of displaying and analyzing the transmitted ECG. To display the ECG data, the program is operated with TCP/IP server mode and static IP address, and to analyze the ECG data, the paper suggests motion artifact remove algorithm including adaptive filter with LMS(least mean square), baseline detection algorithm using predictability estimation theory, a filter with moving weighted factor, low pass filter, peak to peak detection, and interpolation.

Proceedings Article | 24 October 2012 Paper

Wireless Telemedicine Systems for Diagnosing Sleep Disorders with Zigbee Star Network Topology

Sechang Oh, Hyeokjun Kwon, Vijay Varadan

Proceedings Volume 8548, 85482L (2012) https://doi.org/10.1117/12.946115

KEYWORDS: Receivers, Polysomnography, Transmitters, Electroencephalography, Sensors, Electrodes, Stars, Electromyography, Amplifiers, Electrocardiography

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Good sleep is critical for one's overall physical and mental health but more than 50 million Americans have experienced or are suffering from sleep disorders. Nevertheless, 85% of them remain undiagnosed or untreated. They can lead to chronic diseases. Sleep disorders are diagnosed through polysomnography, also known as sleep study, performed in a sleep laboratory overnight. This perturbs his/her daily sleep routine, and consequently, an accurate diagnosis cannot be made. Many companies have been developing home sleep test systems to reduce the cost of sleep studies and provide a more convenience solution to patients. The category of the system varies as type II, type III and type IV according to the type of sleep study. Current systems cannot be easily extended from one type to include a higher type. A patient who has a type III system to diagnose sleep apnea should additionally purchase a type II system which has functions that overlap with a type III system, to evaluate sleep stages. In this paper, we propose a wireless telemedicine system for easy extension of channels using the start network topology of the Zigbee protocol. The HST system consists of two wireless HST devices with a Zigbee module, a wireless HST receiver with both a Zigbee and a Wi-Fi module, and a sever which monitors/saves the physiological signals. One transmitter provides 5 channels for 2x EOG, 2x EEG and EMG to evaluate sleep stages. The other transmitter provides 5 additional channels for ECG, nasal air flow, body position, abdominal/chest efforts and oxygen saturation to diagnose sleep apnea. These two transmitters, acting as routers, and the receiver as a coordinator form a Zigbee star network. The data from each transmitter in the receiver are retransmitted to the monitoring unit through Wi-Fi. By building a star network with Zigbee, channels can be easily extended so that low level systems can be upgraded to higher level systems by simply adding the necessary channels. In addition, the proposed system provides real time monitoring of physiological signals at remote locations using Wi-Fi.

Proceedings Article | 24 October 2012 Paper

Carbon nanotubes polymer nanoparticles inks for healthcare textile

Pratyush Rai, Jungmin Lee, Gyanesh Mathur, Vijay Varadan

Proceedings Volume 8548, 854822 (2012) https://doi.org/10.1117/12.946253

KEYWORDS: Nanocomposites, Particles, Printing, Silver, Carbon nanotubes, Carbon, Medicine, Sensors, Nanoparticles, Composites

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Proceedings Article | 31 March 2012 Paper

Lithium iron phosphates as cathode materials in lithium ion batteries for electric vehicles

Gaojun Wang, Linfeng Chen, Gyanesh Mathur, Vijay Varadan

Proceedings Volume 8344, 83440L (2012) https://doi.org/10.1117/12.915638

KEYWORDS: Lithium, Iron, Ions, Composites, Carbon, Particles, Metals, Sol-gels, Prototyping, Nickel

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Proceedings Article | 31 March 2012 Paper

Size and shape dependence of the electrochemical properties of hematite nanoparticles and their applications in lithium ion batteries

Linfeng Chen, Gaojun Wang, Gyanesh Mathur, Vijay Varadan

Proceedings Volume 8344, 83441J (2012) https://doi.org/10.1117/12.915597

KEYWORDS: Hematite, Nanoparticles, Lithium, Ions, Oxides, Scanning electron microscopy, Metals, Electrodes, Prototyping, Particles

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Proceedings Article | 31 March 2012 Paper

Preparation and characterization of nano-composites with carbon nanotubes and core-shell type polyaniline for the conductive colloidal ink

Jungmin Lee, Vijay Varadan

Proceedings Volume 8344, 834413 (2012) https://doi.org/10.1117/12.915274

KEYWORDS: Particles, Polymers, Nanocomposites, Composites, Polymerization, Electronics, Scanning electron microscopy, Carbon nanotubes, Printing, Chemical elements

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Proceedings Article | 31 March 2012 Paper

The Zigbee wireless ECG measurement system design with a motion artifact remove algorithm by using adaptive filter and moving weighted factor

Hyeokjun Kwon, Sechang Oh, Vijay Varadan

Proceedings Volume 8344, 83440F (2012) https://doi.org/10.1117/12.921505

KEYWORDS: Interference (communication), Electrocardiography, Sensors, Digital filtering, Linear filtering, Signal detection, Motion measurement, Filtering (signal processing), Electronic filtering, Data communications

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The Electrocardiogram(ECG) signal is one of the bio-signals to check body status. Traditionally, the ECG signal was checked in the hospital. In these days, as the number of people who is interesting with periodic their health check increase, the requirement of self-diagnosis system development is being increased as well. Ubiquitous concept is one of the solutions of the self-diagnosis system. Zigbee wireless sensor network concept is a suitable technology to satisfy the ubiquitous concept. In measuring ECG signal, there are several kinds of methods in attaching electrode on the body called as Lead I, II, III, etc. In addition, several noise components occurred by different measurement situation such as experimenter's respiration, sensor's contact point movement, and the wire movement attached on sensor are included in pure ECG signal. Therefore, this paper is based on the two kinds of development concept. The first is the Zibee wireless communication technology, which can provide convenience and simpleness, and the second is motion artifact remove algorithm, which can detect clear ECG signal from measurement subject. The motion artifact created by measurement subject's movement or even respiration action influences to distort ECG signal, and the frequency distribution of the noises is around from 0.2Hz to even 30Hz. The frequencies are duplicated in actual ECG signal frequency, so it is impossible to remove the artifact without any distortion of ECG signal just by using low-pass filter or high-pass filter. The suggested algorithm in this paper has two kinds of main parts to extract clear ECG signal from measured original signal through an electrode. The first part is to extract motion noise signal from measured signal, and the second part is to extract clear ECG by using extracted motion noise signal and measured original signal. The paper suggests several techniques in order to extract motion noise signal such as predictability estimation theory, low pass filter, a filter including a moving weighted factor, peak to peak detection, and interpolation techniques. In addition, this paper introduces an adaptive filter in order to extract clear ECG signal by using extracted baseline noise signal and measured signal from sensor.

Proceedings Article | 31 March 2012 Paper

Synthesis and characterization of thermoelectric ink for renewable energy applications

Jungmin Lee, Hyun Jung Kim, Sechang Oh, Sang Choi, Vijay Varadan

Proceedings Volume 8344, 83440H (2012) https://doi.org/10.1117/12.916635

KEYWORDS: Thermoelectric materials, Printing, Bismuth, Manufacturing, Epoxies, Tellurium, Electrons, Renewable energy, Optical lithography, N-type semiconductors

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Proceedings Article | 31 March 2012 Paper

Wireless brain-machine interface using EEG and EOG: brain wave classification and robot control

Sechang Oh, Prashanth Kumar, Hyeokjun Kwon, Vijay Varadan

Proceedings Volume 8344, 83440U (2012) https://doi.org/10.1117/12.918159

KEYWORDS: Brain-machine interfaces, Electroencephalography, Brain, Electrodes, Eye, Autoregressive models, Feature extraction, Amplifiers, Control systems, Signal processing

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Proceedings Article | 31 March 2012 Paper

Music close to one's heart: heart rate variability with music, diagnostic with e-bra and smartphone

Shantala Hegde, Prashanth Kumar, Pratyush Rai, Gyanesh Mathur, Vijay Varadan

Proceedings Volume 8344, 83440R (2012) https://doi.org/10.1117/12.916793

KEYWORDS: Heart, Electrocardiography, Autoregressive models, Blood pressure, Diagnostics, Medicine, Electrodes, Brain, Modulation, Analytical research

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Proceedings Article | 31 March 2012 Paper

Smart healthcare textile sensor system for unhindered-pervasive health monitoring

Pratyush Rai, Prashanth Kumar, Sechang Oh, Hyeokjun Kwon, Gyanesh Mathur, Vijay Varadan, M. P. Agarwal

Proceedings Volume 8344, 83440E (2012) https://doi.org/10.1117/12.921253

KEYWORDS: Electrocardiography, Blood pressure, Medicine, Sensors, Lead, Electrodes, Calibration, Heart, Point-of-care devices, Signal processing

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Proceedings Article | 25 April 2011 Paper

Synthesis of hematite and maghemite nanotubes and study of their applications in neuroscience and drug delivery

Linfeng Chen, Jining Xie, Kiran Aatre, Justin Yancey, Sahitya Chetan, Malathi Srivatsan, Vijay Varadan

Proceedings Volume 7980, 798008 (2011) https://doi.org/10.1117/12.881843

KEYWORDS: Hematite, Magnetism, Neurons, Scanning electron microscopy, Absorbance, Iron, Sodium, Calibration, Neuroscience, Crystals

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Proceedings Article | 15 April 2011 Paper

Electrochemical investigation of nano-electrodes for biomedical sensing applications in the brain

Courtney Smith, Christopher Bowie, Kyo Song, Hargsoon Yoon, Vijay Varadan, Woong-Ki Kim

Proceedings Volume 7980, 798011 (2011) https://doi.org/10.1117/12.880567

KEYWORDS: Electrodes, Diffusion, Brain, Adsorption, Resistance, Capacitance, Biosensing, Nanostructures, Analytical research, Nanowires

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Proceedings Article | 15 April 2011 Paper

Lithium vanadium oxides (Li(1+x)V3O8) as cathode materials in lithium-ion batteries for soldier portable power systems

Gaojun Wang, Linfeng Chen, Gyanesh Mathur, Vijay Varadan

Proceedings Volume 7980, 798013 (2011) https://doi.org/10.1117/12.885650

KEYWORDS: Lithium, Vanadium, Oxides, Sol-gels, Prototyping, Carbonates, Solid state physics, Solid state electronics, Ions, Electrodes

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Proceedings Article | 15 April 2011 Paper

Printable low-cost sensor systems for healthcare smart textiles

Pratyush Rai, Prashanth Kumar, Sechang Oh, Hyeokjun Kwon, Gyanesh Mathur, Vijay Varadan

Proceedings Volume 7980, 79800E (2011) https://doi.org/10.1117/12.880600

KEYWORDS: Sensors, Electrodes, Electrocardiography, Printing, Electronics, Blood pressure, Arteries, Medicine, Body temperature, Calibration

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Proceedings Article | 15 April 2011 Open Access

Nanotechnology research and development for military and industrial applications

Paul Ruffin, Christina Brantley, Eugene Edwards, J. Keith Roberts, William Chew, Larry Warren, Paul Ashley, Henry Everitt, Eric Webster, John Foreman, Mohan Sanghadasa, Sihon Crutcher, Mark Temmen, Vijay Varadan, Devlin Hayduke, Pae Wu, Christopher Khoury, Yang Yang, Tong-Ho Kim, Tuan Vo-Dinh, April Brown, John Callahan

Proceedings Volume 7980, 798002 (2011) https://doi.org/10.1117/12.878970

KEYWORDS: Sensors, Raman spectroscopy, Combustion, Missiles, Gallium, Acoustics, Nanotechnology, Microfluidics, Carbon, Nanowires

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Proceedings Article | 15 April 2011 Open Access

Development of diagnosis and treatment technology for brain disease using quantum material and nano probe pin device

Uhn Lee, Sang Choi, Vijay Varadan, Kyo Song, Yeonjoon Park

Proceedings Volume 7980, 798003 (2011) https://doi.org/10.1117/12.880453

KEYWORDS: Brain, Sensors, Microwave radiation, Skin, Electrodes, Tissues, Polyurethane, Magnetism, Control systems, Neurons

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Proceedings Article | 14 April 2011 Paper

Design and implementation of a bluetooth-based band-aid pulse rate sensor

Prashanth Kumar, Sechang Oh, Pratyush Rai, Hyeokjun Kwon, Nilanjan Banerjee, Vijay Varadan

Proceedings Volume 7980, 79800P (2011) https://doi.org/10.1117/12.879185

KEYWORDS: Sensors, Blood, Arteries, Blood pressure, Electrocardiography, Ferroelectric polymers, Heart, Medicine, Amplifiers, Diagnostics

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Proceedings Article | 14 April 2011 Paper

Synthesis and characterization of thiol-functionalized polymer as binder in conductive ink

Jungmin Lee, Vijay Varadan

Proceedings Volume 7980, 798009 (2011) https://doi.org/10.1117/12.881820

KEYWORDS: Polymers, Particles, Printing, Nanoparticles, Silver, Scanning electron microscopy, Metals, Electronics, Inkjet technology, Photography

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Proceedings Article | 14 April 2011 Paper

E-bra with nanosensors, smart electronics and smart phone communication network for heart rate monitoring

Vijay Varadan, Prashanth Kumar, Sechang Oh, Gyanesh Mathur, Pratyush Rai, Lauren Kegley

Proceedings Volume 7980, 79800S (2011) https://doi.org/10.1117/12.885649

KEYWORDS: Heart, Sensors, Electrocardiography, Data acquisition, Electrodes, Medicine, Signal processing, Nanosensors, Electronics, Relays

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Proceedings Article | 14 April 2011 Paper

Wireless remote monitoring system for sleep apnea

Sechang Oh, Hyeokjun Kwon, Vijay Varadan

Proceedings Volume 7980, 79800Q (2011) https://doi.org/10.1117/12.879817

KEYWORDS: Sensors, Amplifiers, Receivers, Transmitters, Chest, Electrocardiography, Diagnostics, Signal detection, Heart, Oxygen

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Proceedings Article | 14 April 2011 Paper

Design of electrocardiography measurement system with an algorithm to remove noise

Hyeokjun Kwon, Sechang Oh, Prashanth Kumar, Vijay Varadan

Proceedings Volume 7980, 79800K (2011) https://doi.org/10.1117/12.879919

KEYWORDS: Electrocardiography, Interference (communication), Digital filtering, Sensors, Signal detection, Electronic filtering, Sensor networks, Telecommunications, Linear filtering, Medicine

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Proceedings Article | 31 March 2010 Paper

Low voltage pentacene OTFT integration for smart sensor control circuits

Prashanth Kumar, Pratyush Rai, Gyanesh Mathur, Vijay Varadan

Proceedings Volume 7646, 76460M (2010) https://doi.org/10.1117/12.864248

KEYWORDS: Dielectrics, Transistors, Sensors, Diodes, Semiconducting wafers, Polymers, Resistance, Palladium, Capacitors, Silicon

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Proceedings Article | 31 March 2010 Paper

Homeland security monitoring sensors and early warning relay and diagnostic system

Vijay Varadan, Paul Ruffin, Christina Brantley, Eugene Edwards

Proceedings Volume 7646, 76460K (2010) https://doi.org/10.1117/12.853033

KEYWORDS: Sensors, Carbon nanotubes, Gases, Polymers, Biosensors, Electrodes, Homeland security, Sensing systems, Biosensing, Metals

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Proceedings Article | 31 March 2010 Paper

Organic electronics based pressure sensor towards intracranial pressure monitoring

Pratyush Rai, Vijay Varadan

Proceedings Volume 7646, 764617 (2010) https://doi.org/10.1117/12.849188

KEYWORDS: Sensors, Ferroelectric polymers, Brain, Amplifiers, Organic electronics, Veins, Thin films, Transistors, Logic, Arteries

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Proceedings Article | 31 March 2010 Paper

Nanowire-organic thin film transistor integration and scale up towards developing sensor array for biomedical sensing applications

Prashanth Kumar, Phillip Hankins, Pratyush Rai, Vijay Varadan

Proceedings Volume 7646, 76461M (2010) https://doi.org/10.1117/12.849729

KEYWORDS: Sensors, Action potentials, Ions, Potassium, Transistors, Electrodes, Ischemia, Thin films, Biosensing, Nanowires

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Proceedings Article | 31 March 2010 Paper

Integration of OLEDs in biomedical sensor systems: design and feasibility analysis

Pratyush Rai, Prashanth Kumar, Vijay Varadan

Proceedings Volume 7646, 76460Z (2010) https://doi.org/10.1117/12.849185

KEYWORDS: Organic light emitting diodes, Sensors, Light sources, Polymers, Luminescence, Photons, Biomedical optics, Printing, Electrodes, Systems modeling

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Proceedings Article | 31 March 2010 Paper

Eco green flexible hybrid photovoltaic-thermoelectric solar cells with nanoimprint technology and roll-to-roll manufacturing

Vijay Varadan, Sang Choi

Proceedings Volume 7646, 764605 (2010) https://doi.org/10.1117/12.849597

KEYWORDS: Solar energy, Solar cells, Manufacturing, Photovoltaics, Silicon, Polymers, Thermoelectric materials, Buildings, Nanotechnology, Carbon nanotubes

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Proceedings Article | 31 March 2010 Paper

Application of wireless sensor system on security network

Sechang Oh, Hyeokjun Kwon, Hargsoon Yoon, Vijay Varadan

Proceedings Volume 7646, 76460W (2010) https://doi.org/10.1117/12.849289

KEYWORDS: Sensors, Signal detection, Receivers, Network security, Amplifiers, Sensor networks, Standards development, Internet, Sensing systems, Wireless communications

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Proceedings Article | 31 March 2010 Paper

A systems engineering approach to wireless integration, design, modeling, and analysis of nanosensors, networks, and systems

Seshadri Mohan, Hussain Al-Rizzo, Radu Babiceanu, Taha Elwi, Rabindra Ghimire, Guoliang Huang, Haider Khalil, Daniel Rucker, Chitranjan Singh, Vijay Varadan, Kenji Yoshigoe, Rui Zhu

Proceedings Volume 7646, 76460A (2010) https://doi.org/10.1117/12.849763

KEYWORDS: Antennas, Sensors, Reliability, Telecommunications, Computing systems, Sensor networks, Systems modeling, Brain, Electrodes, Nanowires

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Wireless nano sensors networks are being increasingly applied in many real-world applications, such as structural health monitoring, medical applications, smart clothes, battlefield communications, and intelligent highway systems. A systems approach to such applications require end-to-end infrastructure that includes sensors and sensor networking, wireless communication, reliable backbone networking,, computing infrastructure and other supporting systems. In fact, it fairly clear that sensor systems, communications systems, and computing systems need to interwork together to form a system of systems. The design and implementation of such complex systems need to take into consideration their intended functionality, operational requirements, and expected lifetime. Systems engineering provides the design and implementation framework to successfully bring large complex systems into operation by integrating multiple engineering disciplines into a structured development process, starting with identification of the need, and defining the initial concept, to formulating the requirements to detailed design, development and then, implementation. This paper brings together aspects of research that is being conducted as part of the Arkansas ASSET initiative, which is a multi-campus project supported by NSF Section 2 provides a systems engineering life-cycle modeling approach. Section 3 develops modeling and analysis of nanowires for a biological application. Section 4 provides insights into the design of wireless interfaces to provide wireless capability to wearable sensors for medical applications. Section 5 discusses the application of multiple input multiple output (MIMO) to improve reliability in wireless Section 6 proposes a data-driven adaptive transmission mechanism to improve both data quality and energy efficiency. Section 7 provides insights into the development of protocols for reliable transport of data over a wavelength division multiplexed optical transport network. Section 8 summarizes our findings.

Proceedings Article | 31 March 2010 Paper

Software structure for broadband wireless sensor network system

Hyeokjun Kwon, Sechang Oh, Hargsoon Yoon, Vijay Varadan

Proceedings Volume 7646, 76460X (2010) https://doi.org/10.1117/12.849288

KEYWORDS: Sensors, Local area networks, Sensor networks, Data acquisition, Data communications, Neodymium, Broadband telecommunications, Wireless communications, Control systems, Amplifiers

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SPIE Journal Paper | 1 October 2009

Fabrication of giant magneto resistance sensing devices with vertically grown Co/Cu nanowires on a substrate

Thong Le, Hargsoon Yoon, Linfeng Chen, Roy McCann, Vijay Varadan

JM3, Vol. 8, Issue 04, 043055, (October 2009) https://doi.org/10.1117/12.10.1117/1.3273963

KEYWORDS: Magnetism, Copper, Multilayers, Resistance, Electrodes, Silicon, Crystals, Magnetic sensors, Cobalt, Nanowires

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Proceedings Article | 1 April 2009 Paper

Magnetic nanoparticles and nanotubes for biomedical applications

Linfeng Chen, Jining Xie, Justin Yancey, Malathi Srivatsan, Vijay Varadan

Proceedings Volume 7291, 729108 (2009) https://doi.org/10.1117/12.821550

KEYWORDS: Magnetism, Nanoparticles, Biomedical optics, Nanomaterials, Particles, Nanomedicine, Scanning electron microscopy, Hematite, Nanotechnology, Iron

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Proceedings Article | 1 April 2009 Open Access

Wireless nanosensors and systems (WiNS)

Gail McClure, Vijay Varadan

Proceedings Volume 7291, 729106 (2009) https://doi.org/10.1117/12.820765

KEYWORDS: Electrodes, Sensors, Carbon nanotubes, Magnetism, Neurons, Scanning electron microscopy, Nanosensors, Gold, Systems engineering, Nanowires

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Proceedings Article | 1 April 2009 Paper

Tubular nanostructured materials for bioapplications

Jining Xie, Linfeng Chen, Malathi Srivatsan, Vijay Varadan

Proceedings Volume 7291, 729103 (2009) https://doi.org/10.1117/12.820762

KEYWORDS: Carbon nanotubes, Hematite, Magnetism, Nanomaterials, Electrodes, Carbon, Glucose, Biomedical optics, Scanning electron microscopy, Nanoparticles

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Proceedings Article | 1 April 2009 Paper

Neuroelectronics and modeling of electrical signals for monitoring and control of Parkinson's disease

Ritesh Chintakuntla, Jose Abraham, Vijay Varadan

Proceedings Volume 7291, 72910T (2009) https://doi.org/10.1117/12.829927

KEYWORDS: Neurons, Sodium, Potassium, Brain, Motion models, Ions, Parkinson's disease, Electronics, Device simulation, Circuit switching

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Proceedings Article | 1 April 2009 Paper

Performance modeling and analysis of consumer classes in large scale systems

Sh. Al-Shukri, R. Lenin, S. Ramaswamy, A. Anand, V. Narasimhan, J. Abraham, Vijay Varadan

Proceedings Volume 7291, 72910Y (2009) https://doi.org/10.1117/12.821560

KEYWORDS: Sensor networks, Astatine, Data modeling, Mathematical modeling, Systems modeling, C++, Performance modeling, Human-machine interfaces, Sensors, Field emission displays

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Proceedings Article | 1 April 2009 Paper

Nanodevices for biosensing applications

Hargsoon Yoon, Devesh Deshpande, Vasuda Ramachandran, Phillip Hankins, Vijay Varadan

Proceedings Volume 7291, 72910A (2009) https://doi.org/10.1117/12.821552

KEYWORDS: Electrodes, Glucose, Potassium, Sensors, Gold, Ions, Ischemia, Nanostructures, Biosensing, Nanowires

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Proceedings Article | 1 April 2009 Paper

Design and fabrication of nanowire electrodes on a flexible substrate for detection of myocardial ischemia

Vasuda Ramachandran, Hargsoon Yoon, Vijay Varadan

Proceedings Volume 7291, 729109 (2009) https://doi.org/10.1117/12.821551

KEYWORDS: Potassium, Electrodes, Heart, Gold, Sensors, Nanolithography, Ischemia, Ions, Biosensors, Nanowires

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Proceedings Article | 1 April 2009 Paper

Characterization for organic ion-sensitive field effect transistor response for measurement of physiological potassium ion-concentration measurement

Pratysh Rai, Soyoun Jung, Taeksoo Ji, Vijay Varadan

Proceedings Volume 7291, 72910H (2009) https://doi.org/10.1117/12.821555

KEYWORDS: Sensors, Field effect transistors, Potassium, Ions, Electrodes, Polymers, Transducers, Transistors, Dielectrics, Tantalum

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Proceedings Article | 1 April 2009 Paper

Wireless nanosensor network system

Sechang Oh, Hyukjun Kwon, Lauren Kegley, Hargsoon Yoon, Vijay Varadan

Proceedings Volume 7291, 729111 (2009) https://doi.org/10.1117/12.821561

KEYWORDS: Receivers, Sensors, Internet, Sensing systems, Sensor networks, Wireless communications, Telecommunications, Nanosensors, Computing systems, Mobile devices

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Proceedings Article | 1 April 2009 Paper

Wireless integration, design, modeling, and analysis of nanosensors, networks, and systems: a systems engineering approach

Seshadri Mohan, Hussain Al-Rizzo, Radu Babiceanu, Taha Elwi, Rabindra Ghimire, Guoliang Huang, Daniel Rucker, Ramzi Seker, Fei Song, Vijay Varadan, S. Vimalathithan, Murat Al, Kenji Yoshigoe

Proceedings Volume 7291, 72910G (2009) https://doi.org/10.1117/12.821554

KEYWORDS: Antennas, Sensor networks, Sensors, Systems modeling, Systems engineering, Nanosensors, Computing systems, Network security, Light, Nanowires

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Proceedings Article | 28 March 2009 Paper

New materials for old problems: What can nanomaterials do for biology and neuroscience?

Malathi Srivatsan, Mahadevappa Badanavalu, Justin Yancey, Jining Xie, Linfeng Chen, Philip Hankins, Hargsoon Yoon, Vijay Varadan

Proceedings Volume 7291, 729107 (2009) https://doi.org/10.1117/12.820771

KEYWORDS: Magnetism, Neurons, Electrodes, Nanomaterials, Hematite, Neuroscience, Molecules, Glasses, Scanning electron microscopy, Nanowires

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The emerging field of nanotechnology offers the development of new materials and methods for crucial neuroscience applications namely (a) promoting survival and growth of the neurons, and (b) monitoring physiological signals generated in the nervous system such as excitation, synaptic transmission, release of neurotransmitter molecules and cell-to-cell communication. Such bio-devices will have several novel applications in basic science, laboratory analysis and therapeutic treatments. Our goals in this field of research include (a) development of new biocompatible substrates to guide and promote neuronal growth along specific pathways; (b) designing a neuron-friendly, bio-molecule delivery system for neuroprotection; (c) monitoring of electrical activity from neuron and also from neuronal networks; (d) determining the diffusion and intracellular localization of nanomaterial interacting with neurons at high resolution; and (e) detection of release of neurotransmitter molecules by means of newly designed nanosensors. Here we describe the fabrication and use of magnetic nanotubes and nanowire electrode arrays in studies using a cell culture model of neuronally differentiating rat pheochromocytoma (PC 12) cells. The magnetic nanotubes were fabricated by a template method yielding hematite (α-Fe₂O₃) nanotubes. These nanotubes were coupled with nerve growth factor (NGF). Vertically aligned nanowires were fabricated on glass substrates using the lithography-assisted template bonding (LATB) method. Rat pheochromocytoma (PC12) cells were cultured on these nanotubes and polylysine coated nanowire electrodes. Our results showed that magnetic nanotube bound NGF was available to PC12 cells as they showed significant differentiation into neurons. PC12 cells growing on nanowires in the presence of NGF differentiated into neurons capable of synthesis and release of dopamine upon stimulation. The neurons grew healthy neurites appearing to form synapses with other neurons in the dish. These results show that the magnetic nanotubes were capable of delivering neurotrophic molecules and the nanowire electrodes are neuron-friendly, promote cell to cell communication and can be used as bio-sensors in the nervous system.

SPIE Journal Paper | 1 April 2008

Development of a nanoscale heterostructured glucose sensor using modified microfabrication processes

Devesh Deshpande, Hargsoon Yoon, Aung Khaing, Vijay Varadan

JM3, Vol. 7, Issue 02, 023005, (April 2008) https://doi.org/10.1117/12.10.1117/1.2911639

KEYWORDS: Refraction, Water, Prisms, Refractive index, Thermal optics, Microfluidics, Lithography, Absorbance, Temperature metrology, Electrodes

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Proceedings Article | 31 March 2008 Paper

Synthesis of vertically aligned carbon nanotubes, magnetic nanotubes, and magnetic CNTs for cellular growth and detection

K. Aatre, J. Xie, L. Chen, J. Abraham, V. Varadan

Proceedings Volume 6931, 69310F (2008) https://doi.org/10.1117/12.776255

KEYWORDS: Magnetism, Carbon nanotubes, Scanning electron microscopy, Molecular nanotechnology, Semiconducting wafers, Transmission electron microscopy, Sensors, Silicon, Pathogens, Electrodes

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Proceedings Article | 31 March 2008 Paper

Growth of CNT array for physiological monitoring applications

J. K. Radhakrishnan, H. Bhusan, P. Pandian, K. U. B. Rao, V. C. Padaki, K. Aatre, J. Xie, J. Abraham, V. Varadan

Proceedings Volume 6931, 69310P (2008) https://doi.org/10.1117/12.798231

KEYWORDS: Carbon nanotubes, Electrodes, Scanning electron microscopy, Chemical vapor deposition, Electroencephalography, Argon, Annealing, Titanium, Semiconducting wafers, Carbon

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Proceedings Article | 31 March 2008 Paper

Ion-sensitive field effect transistors for pH and potassium ion concentration sensing: towards detection of myocardial ischemia

Pratyush Rai, Soyoun Jung, Taeksoo Ji, Vijay Varadan

Proceedings Volume 6931, 69310I (2008) https://doi.org/10.1117/12.776205

KEYWORDS: Ions, Potassium, Sensors, Electrodes, Field effect transistors, Oxides, Tantalum, Dielectrics, Ischemia, Oxygen

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Proceedings Article | 26 March 2008 Paper

Low noise multi-channel biopotential wireless data acquisition system for dry electrodes

P. S Pandian, Ashwin Whitchurch, Jose Abraham, Himanshu Bhusan Baskey, J. K. Radhakrishnan, Vijay Varadan, V. C. Padaki, K. U. Bhasker Rao, R. Harbaugh

Proceedings Volume 6931, 69310Q (2008) https://doi.org/10.1117/12.798234

KEYWORDS: Electrodes, Skin, Electrocardiography, Signal processing, Amplifiers, Data acquisition, Electroencephalography, Electromyography, Resistance, Interference (communication)

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The bioelectrical potentials generated within the human body are the result of electrochemical activity in the excitable cells of the nervous, muscular or glandular tissues. The ionic potentials are measured using biopotential electrodes which convert ionic potentials to electronic potentials. The commonly monitored biopotential signals are Electrocardiogram (ECG), Electroencephalogram (EEG) and Electromyogram (EMG). The electrodes used to monitor biopotential signals are Ag-AgCl and gold, which require skin preparation by means of scrubbing to remove the dead cells and application of electrolytic gel to reduce the skin contact resistance. The gels used in biopotential recordings dry out when used for longer durations and add noise to the signals and also prolonged use of gels cause irritations and rashes to skin. Also noises such as motion artifact and baseline wander are added to the biopotential signals as the electrode floats over the electrolytic gel during monitoring. To overcome these drawbacks, dry electrodes are used, where the electrodes are held against the skin surface to establish contact with the skin without the need for electrolytic fluids or gels. The major drawback associated with the dry electrodes is the high skin-electrode impedance in the low frequency range between 0.1-120 Hz, which makes it difficult to acquire clean and noise free biopotential signals. The paper presents the design and development of biopotential data acquisition and processing system to acquire biopotential signals from dry electrodes. The electrode-skin-electrode- impedance (ESEI) measurements was carried out for the dry electrodes by impedance spectroscopy. The biopotential signals are processed using an instrumentation amplifier with high CMRR and high input impedance achieved by boot strapping the input terminals. The signals are band limited by means of a second order Butterworth band pass filters to eliminate noise. The processed biopotential signals are digitized and transmitted wirelessly to a remote monitoring station.

Proceedings Article | 26 March 2008 Paper

Fabrication of flexible and disposable carbon paste-based electrodes and their electrochemical sensing

Lavanya Aryasomayajula, Vijay Varadan

Proceedings Volume 6931, 693105 (2008) https://doi.org/10.1117/12.776289

KEYWORDS: Electrodes, Glucose, Sensors, Carbon, Biosensors, Printing, Signal detection, Blood, Oxygen, Oxidation

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Proceedings Article | 26 March 2008 Paper

Carbon nanotube strain sensors for wearable patient monitoring applications

Jose Abraham, Lavanya Aryasomayajula, Ashwin Whitchurch, Vijay Varadan

Proceedings Volume 6931, 69310J (2008) https://doi.org/10.1117/12.776181

KEYWORDS: Sensors, Carbon nanotubes, Composites, Nanocomposites, Vital signs, Prototyping, Algorithm development, Electronics, Scanning electron microscopy, Fiber optics sensors

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Proceedings Article | 26 March 2008 Paper

Development of potassium ion sensors using polypyrrole electrodes on a polyimide substrate

Vasuda Ramachandran, Hargsoon Yoon, Vijay Varadan

Proceedings Volume 6931, 69310H (2008) https://doi.org/10.1117/12.776834

KEYWORDS: Electrodes, Potassium, Ions, Gold, Sensors, Ischemia, Polymers, Nanolithography, Plating, Nanowires

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Proceedings Article | 21 December 2007 Paper

Low-voltage organic strain sensor on plastic using polymer/high- K inorganic hybrid gate dielectrics

Soyoun Jung, Taeksoo Ji, Vijay Varadan

Proceedings Volume 6798, 679810 (2007) https://doi.org/10.1117/12.759497

KEYWORDS: Dielectrics, Sensors, Tantalum, Polymers, Thin films, Electrodes, Organic electronics, Transistors, Polymeric sensors, Organic semiconductors

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Proceedings Article | 30 April 2007 Paper

Wideband microwave absorber design using micro and nanomaterials

Jose Abraham, T. Shami, Alok Dixit, Rama Dubey, Abhinandan Jain, Vijay Varadan, K. U. Rao

Proceedings Volume 6528, 65281O (2007) https://doi.org/10.1117/12.735860

KEYWORDS: Composites, Carbon, Iron, Microwave radiation, Magnetism, Reflectivity, Nanomaterials, Glasses, Dielectrics, Metals

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Proceedings Article | 11 April 2007 Paper

Nanowire integrated microelectrode arrays for lab-on-a-chip applications

Jose Abraham, Hargsoon Yoon, Vijay Varadan, Ritesh Chintakuntla

Proceedings Volume 6528, 65280O (2007) https://doi.org/10.1117/12.717662

KEYWORDS: Lab on a chip, Electrodes, Biological research, Metals, Silicon, Photoresist materials, Microfluidics, Nanolithography, Chemical analysis, Nanowires

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Proceedings Article | 11 April 2007 Open Access

The role of nanotechnology and nano and micro-electronics in monitoring and control of cardiovascular diseases and neurological disorders

Vijay Varadan

Proceedings Volume 6528, 652813 (2007) https://doi.org/10.1117/12.721762

KEYWORDS: Sensors, Brain, Nanotechnology, Electrodes, Control systems, Neurological disorders, Heart, Ischemia, Ions, Nanowires

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Nanotechnology has been broadly defined as the one for not only the creation of functional materials and devices as well as systems through control of matter at the scale of 1-100 nm, but also the exploitation of novel properties and phenomena at the same scale. Growing needs in the point-of-care (POC) that is an increasing market for improving patient's quality of life, are driving the development of nanotechnologies for diagnosis and treatment of various life threatening diseases. This paper addresses the recent development of nanodiagnostic sensors and nanotherapeutic devices with functionalized carbon nanotube and/or nanowire on a flexible organic thin film electronics to monitor and control of the three leading diseases namely 1) neurodegenerative diseases, 2) cardiovascular diseases, and 3) diabetes and metabolic diseases. The sensors developed include implantable and biocompatible devices, light weight wearable devices in wrist-watches, hats, shoes and clothes. The nanotherapeutics devices include nanobased drug delivery system. Many of these sensors are integrated with the wireless systems for the remote physiological monitoring. The author's research team has also developed a wireless neural probe using nanowires and nanotubes for monitoring and control of Parkinson's disease. Light weight and compact EEG, EOG and EMG monitoring system in a hat developed is capable of monitoring real time epileptic patients and patients with neurological and movement disorders using the Internet and cellular network. Physicians could be able to monitor these signals in realtime using portable computers or cell phones and will give early warning signal if these signals cross a pre-determined threshold level. In addition the potential impact of nanotechnology for applications in medicine is that, the devices can be designed to interact with cells and tissues at the molecular level, which allows high degree of functionality. Devices engineered at nanometer scale imply a controlled manipulation of individual molecules and atoms that can interact with the human body at sub-cellular level. The recent progress in microelectronics and nanosensors crates very powerful tools for the early detection and diagnosis. The nanowire integrated potassium and dopamine sensors are ideal for the monitoring and control of many cardiovascular diseases and neurological disorders. Selected movies illustrating the applications of nanodevices to patients will be shown at the talk.

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Proceedings Article | 11 April 2007 Paper

Design and fabrication of OTFT based flexible piezoelectric sensor

Taeksoo Ji, Mayakuthan Kathiresan, Shiny Nair, Soyoun Jung, Venkatachalam Natarajan, Rama Mohan Rao Vishnubhatla, Vijay Varadan

Proceedings Volume 6528, 65281P (2007) https://doi.org/10.1117/12.735864

KEYWORDS: Sensors, Ferroelectric polymers, Electrodes, Dielectrics, Polymeric sensors, Polymers, Silicon, Polymer thin films, Capacitance, Semiconductors

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Proceedings Article | 11 April 2007 Paper

Development of poly-3-hexylthiophene based ISFET sensors for biomedical applications

Pratyush Rai, Soyoun Jung, Taeksoo Ji, Vijay Varadan

Proceedings Volume 6528, 652815 (2007) https://doi.org/10.1117/12.721764

KEYWORDS: Field effect transistors, Electrodes, Sensors, Biosensors, Dielectrics, Ions, Tantalum, Oxides, Photomicroscopy, Potassium

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Proceedings Article | 11 April 2007 Paper

A total patient monitoring system for point-of-care applications

Ashwin Whitchurch, Jose Abraham, Vijay Varadan

Proceedings Volume 6528, 65280R (2007) https://doi.org/10.1117/12.717664

KEYWORDS: Sensors, Electroencephalography, Electrocardiography, Telecommunications, Analog electronics, Internet, Vital signs, Point-of-care devices, Medicine, Receivers

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Proceedings Article | 11 April 2007 Paper

Glucose sensing based on Pt-MWCNT and MWCNT

Lavanya Aryasomayajula, Jining Xie, Shouyan Wang, Vijay Varadan

Proceedings Volume 6528, 65281K (2007) https://doi.org/10.1117/12.717666

KEYWORDS: Glucose, Electrodes, Sensors, Platinum, Blood, Carbon nanotubes, Signal to noise ratio, Pancreas, Molecules, Minerals

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Proceedings Article | 11 April 2007 Paper

Cylindrical nanocavity and nanowire electrodes for redox cycle dopamine sensing: design, fabrication, and characterization

Phillip Hankins, Hargsoon Yoon, Vijay Varadan

Proceedings Volume 6528, 65281J (2007) https://doi.org/10.1117/12.717665

KEYWORDS: Electrodes, Sensors, In vivo imaging, Gold, Scanning electron microscopy, Nanolithography, 3D surface sensing, Molecules, Nanowires, Oxidation

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Proceedings Article | 11 April 2007 Paper

Bio-inspired electric cilia development for biomedical applications: use of ionic electro-active polymer, nanowire arrays, and micro-stereo-lithography

Hargsoon Yoon, Vasuda Ramachandran, Devesh Deshpande, Vijay Varadan

Proceedings Volume 6528, 652804 (2007) https://doi.org/10.1117/12.717660

KEYWORDS: Polymers, Microfluidics, Platinum, Gold, Sensors, Biomimetics, Electrodes, Nanolithography, Biomedical optics, Nanowires

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Proceedings Article | 11 April 2007 Paper

Development of amperometric glucose sensors with heterostructured nanowire arrays for continuous subcutaneous monitoring

Devesh Deshpande, Hargsoon Yoon, Aung Khaing, Vijay Varadan

Proceedings Volume 6528, 652819 (2007) https://doi.org/10.1117/12.717668

KEYWORDS: Glucose, Electrodes, Sensors, Platinum, Gold, Hydrogen, Polymers, Nanolithography, Nanowires, Oxidation

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Proceedings Article | 11 April 2007 Paper

Synthesis and photonic property study of ZnO nanowires for a real time photodynamic therapy monitoring probe

D. Sridhar, Jining Xie, Jose Abraham, Vijay Varadan

Proceedings Volume 6528, 65281L (2007) https://doi.org/10.1117/12.717667

KEYWORDS: Zinc oxide, Photodynamic therapy, Tumors, Oxygen, Ultraviolet radiation, Gold, Luminescence, Scanning electron microscopy, Zinc, Nanowires

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In this paper, we present how the photonic properties of zinc oxide (ZnO) nanowires can be used to potentially advance the effectiveness of Photodynamic therapy (PDT), one of the most recent and promising approaches among cancer therapies. Presently, PDT employs laser light to activate intravenously or topically administered photosensitizers to give rise to highly reactive singlet oxygen which has a very short lifetime and is capable of biochemical damage to cell membranes of the tumor. A probe that can monitor in real time the penetration depth of the laser in the tumor and also the evolution of the singlet oxygen, which is critical for tumor eradication, is capable of improving the efficacy of PDT quite significantly. Such a probe, by providing real time feedback, can help us determine whether to increase or decrease the light exposure dose and also if further local administration of photosensitizers is required or not. ZnO nanowires are known to be photoconductive and recent research also demonstrated the temperature dependence of the photocurrent in the nanowires. They are also sensitive to blue and other near UV spectra which is same range of activation wavelengths of most photosensitizers, and hence making them a good candidate for a potential PDT monitoring probe. ZnO nanowires were fabricated on silicon substrates by vapor phase deposition using e-beam evaporated gold as a catalyst. Control of the dimensions of the nanowires could be achieved by varying the dimensions of the catalyst by means of e-beam evaporation process. Photoluminescence properties of ZnO nanowires were investigated at UV and near UV wavelengths. Further, ZnO is also known for its antimicrobial properties, thereby ruling out any possibility of bacterial infection because of the implanted probe. This study was done to compliment the existing expertise of our research group in the design and fabrication of several nanowire based probes and microsensors specifically for neuroelectronic and nanomedicine applications.

Proceedings Article | 11 April 2007 Paper

Experimental investigation of magnetic nanotubes in PC-12 neuron cells culturing

Linfeng Chen, Jining Xie, J. Yancey, Malathi Srivatsan, Vijay Varadan

Proceedings Volume 6528, 65280L (2007) https://doi.org/10.1117/12.717970

KEYWORDS: Magnetism, Neurons, Scanning electron microscopy, Transmission electron microscopy, Nervous system, Axons, Nerve, Neuroscience, Glasses, Atomic force microscopy

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Proceedings Article | 11 April 2007 Paper

Piezoelectric 3D nanostructures for developing point-of-care biosensors

Jose Abraham, Sridhar Dubaka, Vijay Varadan, Huajun Zhou, Tierui Zhang, Z. Ryan Tian

Proceedings Volume 6528, 65280V (2007) https://doi.org/10.1117/12.717663

KEYWORDS: Nanostructures, Zinc oxide, Biosensors, Sensors, Point-of-care devices, Heart, Arteries, Nanotechnology, Electronics, Nanowires

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Proceedings Article | 8 January 2007 Paper

A novel strain sensor using carbon nanotubes-organic semiconductor matrix composite on polymeric substrates

Soyoun Jung, Taeksoo Ji, Jining Xie, Vijay Varadan

Proceedings Volume 6414, 641409 (2007) https://doi.org/10.1117/12.695483

KEYWORDS: Sensors, Composites, Semiconductors, Wheatstone bridges, Carbon nanotubes, Microwave radiation, Electrodes, Polymers, Carbon, Polymeric sensors

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Proceedings Article | 14 December 2006 Paper

Enzyme electrodes immobilized on hetero-structured metallic nanowire array for glucose sensing

Hargsoon Yoon, Devesh Deshpande, Ritesh Chintakuntla, Vijay Varadan

Proceedings Volume 6416, 641608 (2006) https://doi.org/10.1117/12.695223

KEYWORDS: Glucose, Gold, Electrodes, Platinum, Sensors, Hydrogen, Nanolithography, Silicon, Scanning electron microscopy, Nanowires

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Proceedings Article | 31 March 2006 Paper

Synthesis of oriented ZnO nanostructure arrays for solar cell applications

D. Sridhar, Jining Xie, Jose Abraham, Vijay Varadan, Sang Choi

Proceedings Volume 6172, 617208 (2006) https://doi.org/10.1117/12.668743

KEYWORDS: Zinc oxide, Solar cells, Glasses, Crystals, Nanostructures, Scanning electron microscopy, Transparent conductors, Electron microscopes, Coating, Nanorods

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Proceedings Article | 31 March 2006 Paper

Modeling of passive wireless sensor modeling for RFID tag applications

Jose Abraham, Vijay Varadan

Proceedings Volume 6172, 617204 (2006) https://doi.org/10.1117/12.668742

KEYWORDS: Sensors, Reflectors, Antennas, Temperature metrology, Gallium, Calibration, Acoustics, Phase measurement, Instrument modeling, Electronics

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Proceedings Article | 31 March 2006 Paper

Nanowire array for wireless neural Probe: modeling and simulation

Ritesh Chintakuntla, Jose Abraham, Vijay Varadan

Proceedings Volume 6172, 61720I (2006) https://doi.org/10.1117/12.668747

KEYWORDS: Neurons, Sodium, Potassium, Circuit switching, Microelectromechanical systems, Device simulation, Motion models, Resistance, Modeling and simulation, Nanowires

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Proceedings Article | 31 March 2006 Paper

Magnetic nanotubes and their potential use in neuroscience applications

Linfeng Chen, Jining Xie, Malathi Srivatsan, Vijay Varadan

Proceedings Volume 6172, 61720J (2006) https://doi.org/10.1117/12.668748

KEYWORDS: Magnetism, Neurons, Neuroscience, Scanning electron microscopy, Modulation, Transmission electron microscopy, Nervous system, Iron, Oxides, Molecules

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Proceedings Article | 31 March 2006 Paper

Organic thin films based sensor applications

Soyoun Jung, Taeksoo Ji, Vijay Varadan

Proceedings Volume 6172, 617209 (2006) https://doi.org/10.1117/12.668745

KEYWORDS: Sensors, Silicon, Thin films, Silicon films, Organic semiconductors, Oxides, Electronics, Dielectrics, Electrodes, Polymers

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Proceedings Article | 31 March 2006 Paper

Neuroelectronics and neurosurgery

Ashwin Whitchurch, Vijay Varadan

Proceedings Volume 6172, 61720S (2006) https://doi.org/10.1117/12.668749

KEYWORDS: Neurons, Brain, Electroencephalography, Electrodes, Nerve, Electronics, Interfaces, Ions, Epilepsy, Carbon nanotubes

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Proceedings Article | 20 March 2006 Paper

Aligned nanowire structures on silicon and flexible substrates and their applications

Hargsoon Yoon, Ritesh Reddy Chintakuntla, Vijay Varadan, Paul Ruffin

Proceedings Volume 6172, 61720H (2006) https://doi.org/10.1117/12.668746

KEYWORDS: Silicon, Thin films, Sensors, Oxides, Tin, Nanolithography, Electrodes, Silicon films, Resistance, Nanowires

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Proceedings Article | 16 May 2005 Paper

Fabrication of three-dimensional structures by micro stereolithography for electromagnetic absorber applications

Taeksoo Ji, Vijay Varadan

Proceedings Volume 5763, (2005) https://doi.org/10.1117/12.608130

KEYWORDS: Bridges, Microelectromechanical systems, Polymers, Electromagnetism, Metals, Ultraviolet radiation, Particles, Fabrication, Stereolithography, Ferromagnetics

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Proceedings Article | 16 May 2005 Paper

Development of nanowire arrays for neural probe

Jose Abraham, Jining Xie, Vijay Varadan

Proceedings Volume 5763, (2005) https://doi.org/10.1117/12.608131

KEYWORDS: Electrodes, Brain, Gold, Silicon, Neurons, Silver, Metals, Nanotechnology, Medicine, Nanowires

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Proceedings Article | 16 May 2005 Paper

Identification of soft drinks using MEMS-IDT microsensors

Jose Abraham, Sonal Karjathkar, Stefany Jacesko, Vijay Varadan, Julian Gardner

Proceedings Volume 5763, (2005) https://doi.org/10.1117/12.608155

KEYWORDS: Liquids, Microsensors, Sensors, Wave propagation, Acoustics, Dielectrics, Antennas, Network security, Free space, Microfluidics

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Proceedings Article | 16 May 2005 Paper

Wilkinson power divider for antenna distribution networks

Taeksoo Ji, Hargsoon Yoon, K. Jose, Vijay Varadan

Proceedings Volume 5763, (2005) https://doi.org/10.1117/12.608125

KEYWORDS: Silicon, Metals, Oxides, Antennas, Interfaces, Electroplating, Ku band, CMOS technology, Thin films, Amorphous silicon

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Proceedings Article | 16 May 2005 Paper

Design of a stacked array antenna system integrated with low temperature co-fired ceramics (LTCC)

Taeksoo Ji, Hargsoon Yoon, K. Jose, Vijay Varadan

Proceedings Volume 5763, (2005) https://doi.org/10.1117/12.608128

KEYWORDS: Antennas, Phase shifts, Phased arrays, Ceramics, Capacitance, System integration, Packaging, Microwave radiation, Telecommunications, Electronic components

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Proceedings Article | 16 May 2005 Paper

Aligned blank and metal encapsulated conducting polymer nanotubules

Jining Xie, Vijay Varadan

Proceedings Volume 5763, (2005) https://doi.org/10.1117/12.608140

KEYWORDS: Nickel, Silver, Scanning electron microscopy, Polymers, Photomicroscopy, Electrodes, Metals, Electroplating, Etching, Chemical elements

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Proceedings Article | 16 May 2005 Paper

Design of pentacene thin film transistors on flexible substrates

Taeksoo Ji, Jining Xie, Vijay Varadan

Proceedings Volume 5763, (2005) https://doi.org/10.1117/12.608129

KEYWORDS: Thin films, Transistors, Polymers, Electrodes, Molecules, Organic semiconductors, Dielectrics, Semiconductors, Silicon, Oxides

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Proceedings Article | 16 May 2005 Paper

Functional carbon nanotube material-based enzyme biosensors for glucose sensing

Nanyan Zhang, Jining Xie, Vijay Varadan

Proceedings Volume 5763, (2005) https://doi.org/10.1117/12.608143

KEYWORDS: Electrodes, Glucose, Carbon nanotubes, Biosensors, Sensors, Silver, Carbon, Biosensing, Hydrogen, Resistance

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Proceedings Article | 16 May 2005 Paper

Wireless microsensor network solutions for neurological implantable devices

Jose Abraham, Ashwin Whitchurch, Vijay Varadan

Proceedings Volume 5763, (2005) https://doi.org/10.1117/12.608124

KEYWORDS: Sensors, Electrodes, Brain, Antennas, Telecommunications, Control systems, Electroencephalography, Epilepsy, Microsensors, Microcontrollers

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The design and development of wireless mocrosensor network systems for the treatment of many degenerative as well as traumatic neurological disorders is presented in this paper. Due to the advances in micro and nano sensors and wireless systems, the biomedical sensors have the potential to revolutionize many areas in healthcare systems. The integration of nanodevices with neurons that are in communication with smart microsensor systems has great potential in the treatment of many neurodegenerative brain disorders. It is well established that patients suffering from either Parkinson’s disease (PD) or Epilepsy have benefited from the advantages of implantable devices in the neural pathways of the brain to alter the undesired signals thus restoring proper function. In addition, implantable devices have successfully blocked pain signals and controlled various pelvic muscles in patients with urinary and fecal incontinence. Even though the existing technology has made a tremendous impact on controlling the deleterious effects of disease, it is still in its infancy. This paper presents solutions of many problems of today's implantable and neural-electronic interface devices by combining nanowires and microelectronics with BioMEMS and applying them at cellular level for the development of a total wireless feedback control system. The only device that will actually be implanted in this research is the electrodes. All necessary controllers will be housed in accessories that are outside the body that communicate with the implanted electrodes through tiny inductively-coupled antennas. A Parkinson disease patient can just wear a hat-system close to the implantable neural probe so that the patient is free to move around, while the sensors continually monitor, record, transmit all vital information to health care specialist. In the event of a problem, the system provides an early warning to the patient while they are still mobile thus providing them the opportunity to react and trigger the feed back system or contact a point-of-care office that can remotely control the implantable system. The remote monitoring technology can be adaptable to EEG monitoring of children with epilepsy, implantable cardioverters/defibrillators, pacemakers, chronic pain management systems, treatment for sleep disorders, patients with implantable devices for diabetes. In addition, the development of a wireless neural electronics interface to detect, transmit and analyze neural signals could help patients with spinal injuries to regain some semblance of mobile activity.

Proceedings Article | 16 May 2005 Paper

Nanowire sensor array for wireless detection and identification of biohazards

Hargsoon Yoon, Biju Philip, Jose Abraham, Taeksoo Ji, Vijay Varadan

Proceedings Volume 5763, (2005) https://doi.org/10.1117/12.608145

KEYWORDS: Sensors, Composites, Thin films, Waveguides, Phase measurement, Phase shifts, Carbon nanotubes, Resistance, Sensor networks, Gas sensors

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Proceedings Article | 16 May 2005 Paper

Design and development of 3-bit polymer MEMS phase shifters

Hargsoon Yoon, Taeksoo Ji, Vijay Varadan

Proceedings Volume 5763, (2005) https://doi.org/10.1117/12.608127

KEYWORDS: Polymers, Microelectromechanical systems, Phase shifts, Silicon, Thin films, Electrodes, Silicon films, Switches, Metals, Bridges

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Proceedings Article | 16 May 2005 Paper

Stability analysis of carbon nanotubes via continuum models

Q. Wang, V. Varadan, G. Zhou

Proceedings Volume 5763, (2005) https://doi.org/10.1117/12.598556

KEYWORDS: Carbon nanotubes, Single walled carbon nanotubes, Analytical research, Composites, Performance modeling, Microelectromechanical systems, Systems modeling, Mechanics, Molecular electronics, Chemical species

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Proceedings Article | 29 July 2004 Paper

Synthesis of Tin Oxide/Carbon Nanotube Composite by Homogeneous Precipitation and Characterizations

Jining Xie, Vijay Varadan

Proceedings Volume 5389, (2004) https://doi.org/10.1117/12.548437

KEYWORDS: Tin, Oxides, Carbon nanotubes, Composites, Lithium, Particles, Nanoparticles, Ions, Scanning electron microscopy, Electrodes

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Proceedings Article | 29 July 2004 Paper

Deep-brain stimulator and control of Parkinson's disease

Vijay Varadan, Robert Harbaugh, Jose Abraham

Proceedings Volume 5389, (2004) https://doi.org/10.1117/12.548438

KEYWORDS: Sensors, Control systems, Antennas, Electrodes, Telecommunications, Gyroscopes, Microcontrollers, Microelectromechanical systems, Brain, Neurological disorders

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The design of a novel feedback sensor system with wireless implantable polymer MEMS sensors for detecting and wirelessly transmitting physiological data that can be used for the diagnosis and treatment of various neurological disorders, such as Parkinson's disease, epilepsy, head injury, stroke, hydrocephalus, changes in pressure, patient movements, and tremors is presented in this paper. The sensor system includes MEMS gyroscopes, accelerometers, and pressure sensors. This feedback sensor system focuses on the development and integration of implantable systems with various wireless sensors for medical applications, particularly for the Parkinson's disease. It is easy to integrate and modify the sensor network feed back system for other neurological disorders mentioned above. The monitoring and control of tremor in Parkinson's disease can be simulated on a skeleton via wireless telemetry system communicating with electroactive polymer actuator, and microsensors attached to the skeleton hand and legs. Upon sensing any abnormal motor activity which represent the characteristic rhythmic motion of a typical Parkinson's (PD) patient, these sensors will generate necessary control pulses which will be transmitted to a hat sensor system on the skeleton head. Tiny inductively coupled antennas attached to the hat sensor system can receive these control pulses, demodulate and deliver it to actuate the parts of the skeleton to control the abnormal motor activity. This feedback sensor system can further monitor and control depending on the amplitude of the abnormal motor activity. This microsystem offers cost effective means of monitoring and controlling of neurological disorders in real PD patients. Also, this network system offers a remote monitoring of the patients conditions without visiting doctors office or hospitals. The data can be monitored using PDA and can be accessed using internet (or cell phone). Cellular phone technology will allow a health care worker to be automatically notified if monitoring indicates an emergency situation. The main advantage of such system is that it can effectively monitor large number of patients at the same time, which helps to compensate the present shortage of health care workers.

Proceedings Article | 29 July 2004 Paper

Nanowire sensor applications based on radio frequency phase shift in coplanar waveguide

Hargsoon Yoon, Biju Philip, Jining Xie, Taeksoo Ji, Vijay Varadan

Proceedings Volume 5389, (2004) https://doi.org/10.1117/12.548434

KEYWORDS: Sensors, Composites, Resistance, Waveguides, Reflection, Thin films, Carbon nanotubes, Gas sensors, Phase shifts, Phase measurement

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Proceedings Article | 29 July 2004 Paper

Development of RF MEMS phase shifters using polymer and ferroelectric thin film

Taeksoo Ji, Hargsoon Yoon, K. Jose, Vijay Varadan

Proceedings Volume 5389, (2004) https://doi.org/10.1117/12.548433

KEYWORDS: Bridges, Microelectromechanical systems, Phase shifts, Polymers, Dielectrics, Electrodes, Polymer thin films, Metals, Ferroelectric polymers, Thin films

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Proceedings Article | 29 July 2004 Paper

Development of compact phase shifters on silicon for monolithic integration of voltage controllers

Hargsoon Yoon, Taeksoo Ji, Jose Abraham, Vijay Varadan

Proceedings Volume 5389, (2004) https://doi.org/10.1117/12.548431

KEYWORDS: Silicon, Phase shifts, Silicon films, Thin films, Signal attenuation, Metals, Waveguides, Dielectrics, Electrodes, Thin film devices

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Proceedings Article | 29 July 2004 Paper

Aligned and coiled carbon nanotubes by microwave chemical vapor deposition

Jining Xie, Vijay Varadan

Proceedings Volume 5389, (2004) https://doi.org/10.1117/12.548435

KEYWORDS: Carbon nanotubes, Carbon, Chemical vapor deposition, Scanning electron microscopy, Microwave radiation, Silver, Transmission electron microscopy, Photomicroscopy, Microelectromechanical systems, Composites

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Proceedings Article | 29 July 2004 Paper

Four-element phased-array antenna systems monolithically integrated on silicon

Taeksoo Ji, Hargsoon Yoon, K. Jose, Vijay Varadan

Proceedings Volume 5389, (2004) https://doi.org/10.1117/12.548432

KEYWORDS: Antennas, Phase shifts, Silicon, Phased arrays, System integration, Waveguides, Dielectrics, Beam steering, Phase shift keying, Microwave radiation

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SPIE Journal Paper | 1 July 2004

Design and performance of bilateral interdigital coplanar waveguide phase shifter for rf communication applications

Hargsoon Yoon, Vijay Varadan

JM3, Vol. 3, Issue 03, (July 2004) https://doi.org/10.1117/12.10.1117/1.1759331

KEYWORDS: Phase shifts, Dielectrics, Thin films, Silicon, Waveguides, Electrodes, Capacitors, Sputter deposition, Metals, Signal attenuation

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Proceedings Article | 14 October 2003 Paper

MEMS-based switchable coplanar-waveguide-fed slot antenna

B. Manimegalai, K. Annaram, S. Karthikeyan, N. Annapoorna, K. Deepa, S. Raju, V. Abhaikumar, Vijay Varadan

Proceedings Volume 5062, (2003) https://doi.org/10.1117/12.514934

KEYWORDS: Antennas, Switches, Microelectromechanical systems, Bridges, Waveguides, Switching, Telecommunications, Extremely high frequency, Silicon, Wireless communications

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Proceedings Article | 14 October 2003 Paper

Chirality-dependent electrical properties of one dimensional single-wall nanotubes (SWNTs)

V. Gayathri, D. Mutharasu, A. Ramasubbu, Vijay Varadan

Proceedings Volume 5062, (2003) https://doi.org/10.1117/12.514833

KEYWORDS: Single walled carbon nanotubes, Graphene, Carbon nanotubes, Nanostructures, Carbon, Ionization, Electrical engineering, Fullerenes, Molecules, Smart materials

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Proceedings Article | 14 October 2003 Paper

Meshfree point interpolation methods for analysis of piezoelectric structures

Gui-Rong Liu, K. Y. Dai, Vijay Varadan

Proceedings Volume 5062, (2003) https://doi.org/10.1117/12.514462

KEYWORDS: Finite element methods, Composites, Transducers, Actuators, Chemical elements, Mechanics, Matrices, Dielectrics, Electromechanical design, Wave propagation

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Proceedings Article | 14 October 2003 Paper

Nanotechnology: MEMS and NEMS and their applications to smart systems and devices

Vijay Varadan

Proceedings Volume 5062, (2003) https://doi.org/10.1117/12.514830

KEYWORDS: Polymers, Microelectromechanical systems, Silicon, Sensors, Ceramics, Actuators, Micromachining, Nanoelectromechanical systems, Acoustics, Carbon

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The microelectronics industry has seen explosive growth during the last thirty years. Extremely large markets for logic and memory devices have driven the development of new materials, and technologies for the fabrication of even more complex devices with features sizes now down at the sub micron and nanometer level. Recent interest has arisen in employing these materials, tools and technologies for the fabrication of miniature sensors and actuators and their integration with electronic circuits to produce smart devices and systems. This effort offers the promise of: (1) increasing the performance and manufacturability of both sensors and actuators by exploiting new batch fabrication processes developed including micro stereo lithographic and micro molding techniques; (2) developing novel classes of materials and mechanical structures not possible previously, such as diamond like carbon, silicon carbide and carbon nanotubes, micro-turbines and micro-engines; (3) development of technologies for the system level and wafer level integration of micro components at the nanometer precision, such as self-assembly techniques and robotic manipulation; (4) development of control and communication systems for MEMS devices, such as optical and RF wireless, and power delivery systems, etc. A novel composite structure can be tailored by functionalizing carbon nano tubes and chemically bonding them with the polymer matrix e.g. block or graft copolymer, or even cross-linked copolymer, to impart exceptional structural, electronic and surface properties. Bio- and Mechanical-MEMS devices derived from this hybrid composite provide a new avenue for future smart systems. The integration of NEMS (NanoElectroMechanical Systems), MEMS, IDTs (Interdigital Transducers) and required microelectronics and conformal antenna in the multifunctional smart materials and composites results in a smart system suitable for sending and control of a variety functions in automobile, aerospace, marine and civil strutures and food and medical industries. This unique combination of technologies also results in novel conformal sensors that can be remotely sensed by an antenna system with the advantage of no power requirements at the sensor site. This paper provides a brief review of MEMS and NEMS based smart systems for various applications mentioned above. Carbon Nano Tubes (CNT) with their unique structure, have already proven to be valuable in their application as tips for scanning probe microscopy, field emission devices, nanoelectronics, H₂-storage, electromagnetic absorbers, ESD, EMI films and coatings and structural composites. For many of these applications, highly purified and functionalized CNT which are compatible with many host polymers are needed. A novel microwave CVD processing technique to meet these requirements has been developed at Penn State Center for the Engineering of Electronic and Acoustic Materials and Devices (CEEAMD). This method enables the production of highly purified carbon nano tubes with variable size (from 5 - 40 nm) at low cost (per gram) and high yield. Whereas, carbon nano tubes synthesized using the laser ablation or arc discharge evaporation method always include impurity due to catalyst or catalyst support. The Penn State research is based on the use of zeolites over other metal/metal oxides in the microwave field for a high production and uniformity of the product. An extended coventional purification method has been employed to purify our products in order to remove left over impurity. A novel composite structure can be tailored by functionalizing carbon nano tubes and chemically bonding them with the polymer matrix e.g. block or graft copolymer, or even cross-linked copolymer, to impart exceptional structural, electronic and surface properties. Bio- and Mechanical-MEMS devices derived from this hybrid composites will be presented.

Proceedings Article | 14 October 2003 Paper

RF-MEMS-based switchable low pass filter

S. Kanthamani, R. SenthilNathan, Gowri Kumar, S. RamyaShankari, V, Sigappi, K. Devaki, V. Abhaikumar, S. Raju, Vijay Varadan

Proceedings Volume 5062, (2003) https://doi.org/10.1117/12.514939

KEYWORDS: Microelectromechanical systems, Switches, Linear filtering, Diodes, Systems modeling, Device simulation, Electronics, Prototyping, Circuit switching, Chlorine

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Proceedings Article | 22 July 2003 Paper

Design of a microfluidic cell using microstereolithography for electronic tongue applications

Stefany Jacesko, Taeksoo Ji, Jose Abraham, Vijay Varadan, Julian Gardner

Proceedings Volume 5055, (2003) https://doi.org/10.1117/12.497446

KEYWORDS: Liquids, Microfluidics, Tongue, Signal attenuation, Principal component analysis, Lithography, Acoustics, Transducers, Ultraviolet radiation, Computer aided design

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Proceedings Article | 22 July 2003 Paper

Bilateral interdigital CPW phase shifter using BaSrTiO3 thin film on poly-Si/Si substrate for electronically steerable antenna architecture

Hargsoon Yoon, K. Vinoy, Jose Abraham, Vijay Varadan

Proceedings Volume 5055, (2003) https://doi.org/10.1117/12.497436

KEYWORDS: Phase shifts, Dielectrics, Thin films, Silicon, Signal attenuation, Waveguides, Electrodes, Sputter deposition, Antennas, Silicon films

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Proceedings Article | 22 July 2003 Paper

Microsensors and wireless system for monitoring epilepsy

Ashwin Whitchurch, B. Ashok, Raman Kumaar, K. Sarukesi, K. Jose, Vijay Varadan

Proceedings Volume 5055, (2003) https://doi.org/10.1117/12.497443

KEYWORDS: Epilepsy, Electroencephalography, Electrodes, Brain, Amplifiers, Microcontrollers, Microsensors, Computing systems, Neurons, Visualization

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Proceedings Article | 22 July 2003 Paper

Noninvasive biosensor and wireless interrogating system for glucose in blood

Vijay Varadan, Ashwin Whitchurch, K. Sarukesi

Proceedings Volume 5055, (2003) https://doi.org/10.1117/12.497445

KEYWORDS: Glucose, Blood, Sensors, Skin, Tissues, Molecules, Light emitting diodes, Temperature metrology, Calibration, Polarimetry

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Proceedings Article | 22 July 2003 Paper

Polymer- and carbon nanotube-based MEMS accelerometer with modified organic electronics and thin film transistor

Vijay Varadan

Proceedings Volume 5055, (2003) https://doi.org/10.1117/12.497439

KEYWORDS: Polymers, Microelectromechanical systems, Carbon nanotubes, Silicon, Thin films, Electrodes, Semiconductors, Sensors, Transistors, Ultraviolet radiation

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Proceedings Article | 22 July 2003 Paper

Microstereolithography for polymer-based MEMS

Vijay Varadan, Jining Xie

Proceedings Volume 5055, (2003) https://doi.org/10.1117/12.497459

KEYWORDS: Polymers, Microwave radiation, Microelectromechanical systems, Chemical vapor deposition, Carbon nanotubes, Ultraviolet radiation, Silicon, Actuators, Stereolithography, Metals

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Microfabrication techniques such as bulk micromachining and surface micromachining currently employed to conceive MEMS are largely derived from the standard IC and microelectronics technology. Even though many MEMS devices with integrated electronics have been achieved by using the traditional micromachining techniques, some limitations have nevertheless to be underlined: 1) these techniques are very expensive and need specific installations as well as a cleanroom environment, 2) the materials that can be used up to now are restricted to silicon and metals, 3) the manufacture of 3D parts having curved surfaces or an important number of layers is not possible. Moreover, for some biological applications, the materials used for sensors must be compatible with human body and the actuators need to have high strain and displacement which the current silicon based MEMS do not provide. It is thus natural for the researchers to 'look' for alternative methods such as Microstereolithography (MSL) to make 3D sensors and actuators using polymeric based materials. For MSL techniques to be successful as their silicon counterparts, one has to come up with multifunctional polymers with electrical properties comparable to silicon. These multifunctional polymers should not only have a high sensing capability but also a high strain and actuation performance. A novel UV-curable polymer uniformly bonded with functionalized nanotubes was synthesized via a modified three-step in-situ polymerization. Purified multi-walled nanotubes, gained from the microwave chemical vapor deposition method, were functionalized by oxidation. The UV curable polymer was prepared from toluene diisocyanate (TDI), functionalized nanotubes, and 2-hydroxyethyl methacrylate (HEMA). The chemical bonds between -NCO groups of TDI and -OH, -COOH groups of functionalized nanotubes help for conceiving polymeric based MEMS devices. A cost effective fabrication techniques was presented using Micro Stereo Lithography and an example of a micropump was also described. The wireless concept of the device has many applications including implanted medical delivery systems, chemical and biological instruments, fluid delivery in engines, pump coolants and refrigerants for local cooling of electronic components.

Proceedings Article | 22 July 2003 Paper

Wireless tuning fork gyroscope for biomedical applications

Jose Abraham, Vijay Varadan, Ashwin Whitchurch, K. Sarukesi

Proceedings Volume 5055, (2003) https://doi.org/10.1117/12.497455

KEYWORDS: Sensors, Gyroscopes, Biomedical optics, Telecommunications, Human-computer interaction, Tuning fork gyroscopes, Sensing systems, Reliability, Microelectromechanical systems, Analog electronics

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Proceedings Article | 22 July 2003 Paper

UV-curable polymers with functionalized carbon nanotubes for MEMS

Jining Xie, Nanyan Zhang, Manton Guers, Vijay Varadan

Proceedings Volume 5055, (2003) https://doi.org/10.1117/12.497448

KEYWORDS: Polymers, Ultraviolet radiation, Carbon nanotubes, FT-IR spectroscopy, Microelectromechanical systems, Polymerization, Phase shifts, Microwave radiation, X-rays, Photoemission spectroscopy

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Proceedings Article | 22 July 2003 Paper

Large-scale microwave CVD system for synthesis of carbon nanotubes

Vijay Varadan, Jining Xie

Proceedings Volume 5055, (2003) https://doi.org/10.1117/12.497449

KEYWORDS: Microwave radiation, Chemical vapor deposition, Carbon nanotubes, Carbon, Scanning electron microscopy, Microelectromechanical systems, Zeolites, Transmission electron microscopy, Polymers, Cobalt

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Proceedings Article | 22 July 2003 Paper

Coiled carbon nanotubes: their structural and electrical properties

Jining Xie, Kingsuk Mukhopadyay, J. Yadev, Vijay Varadan

Proceedings Volume 5055, (2003) https://doi.org/10.1117/12.497450

KEYWORDS: Carbon nanotubes, Carbon, Chemical vapor deposition, Microwave radiation, Nickel, Iron, Scanning electron microscopy, Transmission electron microscopy, Nanocomposites, Particles

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Proceedings Article | 22 July 2003 Paper

Carbon nanotubes, fillers, and FSS as potential EM absorbers

Roopashree Tellakula, Yanan Sha, K. Vinoy, K. Jose, Vijay Varadan, T. Shami, R. Jain, D. Lal, C. Neo

Proceedings Volume 5055, (2003) https://doi.org/10.1117/12.497456

KEYWORDS: Composites, Carbon, Reflection, Carbon nanotubes, Dielectrics, Absorption, Metals, Microwave radiation, Polyurethane, FSS based metamaterials

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Proceedings Article | 24 April 2003 Paper

Polymer-based MEMS accelerometer with modified organic electronics and thin film transistor

Vijay Varadan

Proceedings Volume 5116, (2003) https://doi.org/10.1117/12.510487

KEYWORDS: Polymers, Microelectromechanical systems, Carbon nanotubes, Silicon, Thin films, Sensors, Semiconductors, Electrodes, Ultraviolet radiation, Polymer thin films

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Proceedings Article | 24 April 2003 Paper

Three-dimensional polymer MEMS with functionalized carbon nanotubes by microstereolithography

Vijay Varadan, Jining Xie

Proceedings Volume 5116, (2003) https://doi.org/10.1117/12.510486

KEYWORDS: Polymers, Microwave radiation, Carbon nanotubes, Chemical vapor deposition, Microelectromechanical systems, Ultraviolet radiation, Actuators, Silicon, Stereolithography, Metals

Read Abstract +

Microfabrication techniques such as bulk micromachining and surface micromachining currently employed to conceive MEMS are largely derived from the standard IC and microelectronics technology. Even though many MEMS devices with integrated electronics have been achieved by using the traditional micromachining techniques, some limitations have nevertheless to be underlined: 1) these techniques are very expensive and need specific installations as well as a cleanroom environment, 2) the materials that can be used up to now are restricted to silicon and metals, 3) the manufacture of 3D parts having curved surfaces or an important number of layers is not possible. Moreover, for some biological applications, the materials used for sensors must be compatible with human body and the actuators need to have high strain and displacement which the current silicon based MEMS do not provide. It is thus natural for the researchers to look for alternative methods such as Microstereolithography (MSL) to make 3D sensors and actuators using polymeric based materials. For MSL techniques to be successful as their silicon counterparts, one has to come up with multifunctional polymers with electrical properties comparable to silicon. These multifunctional polymers should not only have a high sensing capability but also a high strain and actuation performance. A novel UV-curable polymer uniformly bonded with functionalised nanotubes was synthesized via a modified three-step in-situ polymerization. Purified multi-walled nanotubes, gained from the microwave chemical vapor deposition method, were functionalised by oxidation. The UV curable polymer was prepared from toluene diisocyantae (TDI), functionalised nanotubes, and 2-hydroxyethyl methacrylate (HEMA). The chemical bonds between -NCO groups of TDI and -OH, -COOH groups of functionalised nanotubes help for conceiving polymeric based MEMS devices. A cost effective fabrication techniques was presented using Micro Stereo Lithography and an example of a micropump was also described. The wireless concept of the device has many applications including implanted medical delivery systems, chemical and biological instruments, fluid delivery in engines, pump coolants and refrigerants for local cooling of electronic components.

Proceedings Article | 18 April 2003 Paper

Wireless patient monitoring on shoe for the assessment of foot dysfunction: an overview

Jose Abraham, Ashwin Whitchurch, Vijay Varadan, Karunakaran Sarukesi

Proceedings Volume 5119, (2003) https://doi.org/10.1117/12.499186

KEYWORDS: Gyroscopes, Sensors, Human-machine interfaces, Computing systems, Microcontrollers, Sensing systems, Analog electronics, Tissues, Injuries, Signal detection

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Proceedings Article | 18 April 2003 Paper

Investigation into the future of RFID in biomedical applications

Lucas Ricciardi, Inke Pitz, Said Al-Sarawi, Vijay Varadan, Derek Abbott

Proceedings Volume 5119, (2003) https://doi.org/10.1117/12.501209

KEYWORDS: Polymers, Antennas, Acoustics, Skin, Biomedical optics, Fractal analysis, Signal attenuation, Sensors, Transducers, Actuators

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Proceedings Article | 17 January 2003 Paper

Noninvasive biosensor for hypoglycemia

Vijay Varadan, Ashwin Whitchurch, Karunakaran Sarukesi

Proceedings Volume 4982, (2003) https://doi.org/10.1117/12.479565

KEYWORDS: Glucose, Blood, Sensors, Skin, Biosensors, Brain, Proteins, Calibration, Molecules, Refraction

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Proceedings Article | 16 January 2003 Paper

RF MEMS and reconfigurable antennas for communication systems

K. Vinoy, Hargsoon Yoon, Taeksoo Ji, Vijay Varadan

Proceedings Volume 4981, (2003) https://doi.org/10.1117/12.479562

KEYWORDS: Antennas, Microelectromechanical systems, Phase shifts, Switches, Bridges, Fractal analysis, Capacitance, Telecommunications, Polymers, Silicon

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Proceedings Article | 16 January 2003 Paper

Wireless microsensors for health monitoring of aircraft structures

Vijay Varadan

Proceedings Volume 4981, (2003) https://doi.org/10.1117/12.479561

KEYWORDS: Sensors, Microsensors, Antennas, Gyroscopes, Microelectromechanical systems, Sensing systems, Acoustics, Remote sensing, Transducers, Microelectronics

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The integration of MEMS, IDTs (interdigital transducers) and required microelectronics and conformal antennas to realize programmable, robust and low cost passive microsensors suitable for many military structures and systems including aircraft, missiles and munitions is presented in this paper. The technology is currently being applied to the structural health monitoring of critical aircraft components. The approach integrates acoustic emission, strain gauges, MEMS accelerometers, gyroscopes and vibration monitoring devices with signal processing electronics to provide real-time indicators of incipient failure of aircraft components with a known history of catastrophic failure due to fracture. Recently a combination of the need for safety in the air and the desire to control costs is encouraging the use of in-flight monitoring of aircraft components and systems using light-weight, wireless and cost effective microsensors and MEMS. An in-situ Aircraft structural health monitoring (ASHM) system, with sensors embedded in the composite structure or surface-mounted on the structure, would permit the timely detection of damage in aircraft. Micromachining offers the potential for fabricating a range of microsensors and MEMS for structural applications including load, vibration and acoustics characterization and monitoring. Such microsensors are extremely small; they can be embedded into structural materials, can be mass-produced and are therefore potentially cheap. Additionally a range of sensor types can be integrated onto a single chip with built-in electronics and ASIC (Application Specific Integrated Circuit), providing a low power Microsystems. The smart sensors are being developed using the standard microelectronics and micromachining in conjunction with novel Penn State smart electronics or wireless communication systems suitable for condition monitoring of aircraft structures in-flight. A hybrid accelerometer and gyroscope in a single chip suitable for inertial navigation system and other microsensors for health monitoring and condition-based maintenance of structures, drag sensing and control of aircraft, strain and deflection of structures and systems, ice sensing on aircraft, remote temperature and humidity measurement of propellant in munitions, chemical sensing, etc. are discussed.

Proceedings Article | 15 January 2003 Paper

Three-dimensional polymer MEMS with functionalized carbon nanotubes by micro-stereo-lithography

Vijay Varadan, Jining Xie

Proceedings Volume 4979, (2003) https://doi.org/10.1117/12.479567

KEYWORDS: Polymers, Microwave radiation, Carbon nanotubes, Microelectromechanical systems, Chemical vapor deposition, Ultraviolet radiation, Silicon, Actuators, Stereolithography, Metals

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Microfabrication techniques such as bulk micromachining and surface micromachining currently employed to conceive MEMS are largely derived from the standard IC and microelectronics technology. Even though many MEMS devices with integrated electronics have been achieved by using the traditional micromachining techniques, some limitations have nevertheless to be underlined: 1) these techniques are very expensive and need specific installations as well as a cleanroom environment, 2) the materials that can be used up to now are restricted to silicon and metals, 3) the manufacture of 3D parts having curved surfaces or an important number of layers is not possible. Moreover, for some biological applications, the materials used for sensors must be compatible with human body and the actuators need to have high strain and displacement which the current silicon based MEMS do not provide. It is thus natural for the researchers to look for alternative methods such as Microstereolithography (MSL) to make 3D sensors and actuators using polymeric based materials. For MSL techniques to be successful as their silicon counterparts, one has to come up with multifunctional polymers with electrical properties comparable to silicon. These multifunctional polymers should not only have a high sensing capability but also a high strain and actuation performance. A novel UV-curable polymer uniformly bonded with functionalized nanotubes was synthesized via a modified three-step in-situ polymerization. Purified multi-walled nanotubes, gained from the microwave chemical vapor deposition method, were functionalized by oxidation. The UV curable polymer was prepared from toluene diisocyanate (TDI), functionalized nanotubes, and 2 hydroxyethyl methacrylate (HEMA). The chemical bonds between NCO groups of TDI and OH, COOH groups of functionalized nanotubes help for conceiving polymeric based MEMS devices. A cost effective fabrication techniques was presented using Micro Stereo Lithography and an example of a micropump was also described. The wireless concept of the device has many applications including implanted medical delivery systems, chemical and biological instruments, fluid delivery in engines, pump coolants and refrigerants for local cooling of electronic components.

Proceedings Article | 14 November 2002 Paper

Wireless system for long-term EEG monitoring of absence epilepsy

Ashwin Whitchurch, B. Ashok, R. Kumaar, K. Saurkesi, Vijay Varadan

Proceedings Volume 4937, (2002) https://doi.org/10.1117/12.473344

KEYWORDS: Epilepsy, Electroencephalography, Electrodes, Amplifiers, Brain, Microcontrollers, Computing systems, Electronic filtering, Head, Neurons

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Proceedings Article | 14 November 2002 Paper

Trade-offs for wireless transcutaneous rf communication in biotelemetric applications

Inke Pitz, Leonard Hall, Hedley Hansen, Vijay Varadan, Chris Bertram, Simon Maddocks, Stefan Enderling, David Saint, Said Al-Sarawi, Derek Abbott

Proceedings Volume 4937, (2002) https://doi.org/10.1117/12.476427

KEYWORDS: Antennas, Polymers, Acoustics, Actuators, Transducers, Ferroelectric polymers, Wave propagation, Polymer thick film flex circuits, Polymeric actuators, RF communications

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Proceedings Article | 14 November 2002 Paper

Noninvasive biosensor and wireless interrogating system for hypoglycemia

Vijay Varadan, Ashwin Whitchurch, K. Saukesi

Proceedings Volume 4937, (2002) https://doi.org/10.1117/12.473345

KEYWORDS: Glucose, Sensors, Skin, Blood, Tissues, Molecules, Light emitting diodes, Calibration, Polarimetry, In vivo imaging

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Proceedings Article | 14 November 2002 Paper

UV-curable polymers with chemically-bonded carbon nanotubes for MEMS applications

Jining Xie, Nanyan Zhang, Manton Guers, Vijay Varadan

Proceedings Volume 4935, (2002) https://doi.org/10.1117/12.473338

KEYWORDS: Polymers, Carbon nanotubes, Ultraviolet radiation, FT-IR spectroscopy, Microelectromechanical systems, Polymerization, Phase shifts, Composites, Microwave radiation, X-rays

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Proceedings Article | 14 November 2002 Paper

Wireless microsensors for health monitoring of structures

Vijay Varadan

Proceedings Volume 4935, (2002) https://doi.org/10.1117/12.473337

KEYWORDS: Sensors, Antennas, Microsensors, Microelectromechanical systems, Transducers, Wave propagation, Acoustics, Microelectronics, Telecommunications, Semiconducting wafers

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Proceedings Article | 13 November 2002 Paper

Three-dimensional polymer MEMS with functionalized carbon nanotubes by microstereolithography

Vijay Varadan, Jining Xie

Proceedings Volume 4936, (2002) https://doi.org/10.1117/12.473342

KEYWORDS: Polymers, Carbon nanotubes, Microwave radiation, Microelectromechanical systems, Chemical vapor deposition, Ultraviolet radiation, Silicon, Stereolithography, Actuators, Lithography

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Microfabrication techniques such as bulk micromachining and surface micromachining currently employed to conceive MEMS are largely derived from the standard IC and microelectronics technology. Even though many MEMS devices with integrated electronics have been achieved by using the traditional micromachining techniques, some limitations have nevertheless to be underlined: 1) these techniques are very expensive and need specific installations as well as a cleanroom environment, 2) the materials that can be used up to now are restricted to silicon and metals, 3) the manufacture of 3D parts having curved surfaces or an important numberof layers is not possible. Moreover, for some biological applications, the materials used for sensors must be compatible with human body and the actuators need to have high strain and displacement which the current silicon based MEMS do not provide. It is thus natural for the researchers to 'look' for alternative methods such as Microstereolithography (MSL) to make 3D sensors and actuators using polymeric based materials. For MSL techniques to be successful as their silicon counterparts, one has to come up with multifunctional polyers with electrical properties comparable to silicon. These multifunctional polymers should not only have a high sensing capability but also a high strain and actuation performance. A novel UV-curable polymer uniformly bonded with functionalized nanotubes was synthesized via a modified three-step in-sity polumerization. Purified multi-walled nanotubes, gained from the microwave chemical vapor deposition method, were functionalized by oxidation. The UV curable polymer was prepared from toluene diisocyanate (TDI), functionalized nanotubes, and 2-hydroxyethyl methacrylate (HEMA). The chemical bonds between -NCO groups of TDI and -OH, -COOH groups of functionalized nanotubes help for conceiving polymeric based MEMS devices. A cost effective fabrication techniques was presented using Micro Stereo Lithography and an example of a micropump was also described. The wireless concept of the device has many applications including implanted medical delivery systems, chemical and biological instruments, fluid delivery engines, pump coolants and refrigerants for local cooling of electronic components.

Proceedings Article | 13 November 2002 Paper

Large-scale synthesis of single- and multiwalled carbon nanotubes by microwave CVD

Vijay Varadan, Jining Xie

Proceedings Volume 4936, (2002) https://doi.org/10.1117/12.473343

KEYWORDS: Microwave radiation, Chemical vapor deposition, Carbon nanotubes, Carbon, Scanning electron microscopy, Cobalt, Zeolites, Polymers, Microelectromechanical systems, Transmission electron microscopy

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Proceedings Article | 11 July 2002 Paper

Integrated MOSFET-based hydrophone device for underwater applications

Bei Zhu, Vijay Varadan

Proceedings Volume 4700, (2002) https://doi.org/10.1117/12.475021

KEYWORDS: Field effect transistors, Ferroelectric polymers, Acoustics, Silicon, Amplifiers, Semiconducting wafers, Oxides, Polymers, Interfaces, Microelectromechanical systems

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Proceedings Article | 11 July 2002 Paper

Carbon and ceramic microcoils for MEMS by microwave CVD

Jining Xie, Chiauling Ong, Vijay Varadan

Proceedings Volume 4700, (2002) https://doi.org/10.1117/12.475031

KEYWORDS: Carbon, Microwave radiation, Chemical vapor deposition, Ceramics, Nickel, Titanium, Microelectromechanical systems, Toxic industrial chemicals, Scanning electron microscopy, Chemical species

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Proceedings Article | 11 July 2002 Paper

Three-dimensional MEMS with functionalized carbon nanotubes

Vijay Varadan, Jining Xie

Proceedings Volume 4700, (2002) https://doi.org/10.1117/12.475024

KEYWORDS: Polymers, Carbon nanotubes, Microwave radiation, Microelectromechanical systems, Chemical vapor deposition, Ultraviolet radiation, Actuators, Stereolithography, Silicon, Metals

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Proceedings Article | 11 July 2002 Paper

Optimized multilayered graded fractal FSS: microgenetic algorithm and comparison with experiment

Yanan Sha, K. Vinoy, K. Jose, C. Neo, Vijay Varadan

Proceedings Volume 4700, (2002) https://doi.org/10.1117/12.475038

KEYWORDS: Fractal analysis, Dielectrics, Microwave radiation, Composites, FSS based metamaterials, Carbon, Radar, Reflection, Multilayers, Optimization (mathematics)

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Proceedings Article | 11 July 2002 Paper

Numerical simulation of a surface acoustic wave (SAW) gyroscope using HP EEsof

Anshu Mehta, K. Jose, Vijay Varadan

Proceedings Volume 4700, (2002) https://doi.org/10.1117/12.475028

KEYWORDS: Gyroscopes, Acoustics, Sensors, Resonators, Reflectors, Particles, Numerical simulations, Navigation systems, Crystals, Wave propagation

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Proceedings Article | 11 July 2002 Paper

RF MEMS phase shifter by microstereolithography on silicon

Taeksoo Ji, K. Vinoy, Vijay Varadan

Proceedings Volume 4700, (2002) https://doi.org/10.1117/12.475017

KEYWORDS: Microelectromechanical systems, Bridges, Phase shifts, Polymers, Silicon, Fabrication, Capacitance, Metals, Computer aided design, Molecular bridges

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Proceedings Article | 11 July 2002 Paper

Implemetation of local area wireless sensor networks using Bluetooth

Vibha Ravindran, Vijay Varadan

Proceedings Volume 4700, (2002) https://doi.org/10.1117/12.475037

KEYWORDS: Sensor networks, Sensors, Human-computer interaction, Interfaces, Environmental sensing, Data communications, Transducers, Temperature metrology, Standards development, Wireless communications

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Proceedings Article | 11 July 2002 Paper

Wireless health monitoring of cracks in structures with MEMS-IDT sensors

Jae-Sung Kim, K. Vinoy, Vijay Varadan

Proceedings Volume 4700, (2002) https://doi.org/10.1117/12.475048

KEYWORDS: Sensors, Microelectromechanical systems, Microsensors, Antennas, Transducers, Sensing systems, Remote sensing, Nondestructive evaluation, Acoustics, Microelectronics

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The integration of MEMS, IDTs and required microelectronics and conformal antennas to realize programmable, robust and low cost passive microsensors suitable for many military structures and systems including aircraft, missiles and munitions is presented in this paper. The technology is currently being applied to the structural health monitoring of accelerometers, gyroscopes and vibration monitoring devices with signal processing electronics to provide real- time indicators of incipient failure of aircraft components with a known history of catastrophic failure due to fracture. Recently a combination of the need for safety in the air and the desire to control costs is encouraging the use of in-flight monitoring of aircraft components and systems using light-weight, wireless and cost effective microsensors and MEMS. An in-situ Aircraft structural health monitoring system, with sensors embedded in the composite structure or surface-mounted on the structure, would permit the timely detection of damage in aircraft. Micromachining offers the potential for fabricating a range of microsensors and MEMS for structural applications including load, vibration and acoustics characteristics and monitoring. Such microsensors are extremely small; they can be embedded into structural materials, can be mass-produced and are therefore potentially cheap. Additionally a range of sensor types can be integrated onto a single chip with built-in electronics and ASIC, providing a low power microsystem. The smart sensors are being developed using the standard microelectronics and micromachining in conjunction with novel Penn State smart electronics or wireless communication systems suitable for condition monitoring of aircraft structures in-flight. A hybrid accelerometer and gyroscope in a single chip suitable for inertial navigation system and other microsensors for health monitoring and condition-based maintenance of structures, drag sensing and control of aircraft, strain and deflection of structures and systems, ice sensing on aircraft, remote temperature and humidity measurement of propellant in munitions, chemical sensing, etc. are discussed.

Proceedings Article | 11 July 2002 Paper

Wave transmission and attenuation characteristics of EAP

Jaehwan Kim, Joon-Hyung Kim, Vasundara Varadan, Vijay Varadan

Proceedings Volume 4695, (2002) https://doi.org/10.1117/12.475197

KEYWORDS: Electroactive polymers, Acoustics, Electrodes, Signal attenuation, Aluminum, Polymers, Wave propagation, Silicon, Actuators, Scanning probe lithography

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Proceedings Article | 10 July 2002 Paper

Rayleigh-Ritz/boundary element modeling approach for active/passive control

Senthil Gopinathan, Vasundara Varadan, Vijay Varadan

Proceedings Volume 4693, (2002) https://doi.org/10.1117/12.475231

KEYWORDS: Acoustics, Chemical elements, Foam, Interfaces, Signal attenuation, Control systems design, Aluminum, Bismuth, Systems modeling, Matrices

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Proceedings Article | 21 November 2001 Paper

Design of reconfigurable fractal antennas and rf MEMS for spaced-based communication systems

K. Vinoy, Vijay Varadan

Proceedings Volume 4591, (2001) https://doi.org/10.1117/12.449148

KEYWORDS: Antennas, Fractal analysis, Switches, Microelectromechanical systems, Satellites, Phase shifts, Telecommunications, Satellite communications, Semiconductors, Radar

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Proceedings Article | 21 November 2001 Paper

Hybrid design of an application-specific integrated chip for frequency-to-digital conversion

Neranjen Ramalingam, Vijay Varadan

Proceedings Volume 4591, (2001) https://doi.org/10.1117/12.449154

KEYWORDS: Clocks, Multiplexers, Real-time computing, Signal processing, Adaptive optics, Signal generators, Data conversion, Frequency conversion, Integrated circuits, Digital electronics

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Proceedings Article | 21 November 2001 Paper

Wireless navigation inertial sensors on a single chip with bluetooth technology

Vijay Varadan, K.A. Jose

Proceedings Volume 4591, (2001) https://doi.org/10.1117/12.449156

KEYWORDS: Sensors, Gyroscopes, Reflectors, Acoustics, Antennas, Microelectromechanical systems, Wave propagation, Silicon, Transducers, Wave sensors

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The inertial navigation system uses both gyroscopes and accelerometers to measure the state of motion of a target or a vehicle by sensing the changes in that state caused by accelerations. The required features in many of these applications are high precision, wide dynamic range and wide frequency range. In this paper, recent advances made on Wireless MEMS-IDT based accelerometers and gyroscopes are presented. The concept and design principles underlying a MEMS-IDT (Interdigital Transducer) based accelerometer and gyroscope are based on using surface acoustic waves (SAW) and polysilicon seismic mass for acceleration and proff mass for gyro. This unique concept is a departure from the conventional comb driven MEMS accelerometer design. By designing the seismic mass of the accelerometer to float just above a high frequency Rayleigh Surface Acoustic Wave Sensor (SAWS), we are able to realize the accuracy and versatility required for the measurement of accelerations from 10^-6g to 100g. The gyro design is based on the combination of Surface Acoustic Wave Resonator (SAWR) and Surface Acoustic Wave Sensor, which operates at the Rayleigh mode. They possess typical advantages of MEMS sensors including the additional benefits of robustness, excellent sensitivity (about 1 deg./hr.), surface conformability and durability. The transmitter IDT creates SAW (Surface Acoustic Wave) that propagates back and forth between the reflectors and forms a standing wave pattern within the cavity space between the IDTs. The particles at the anti- nodes of standing wave pattern experience large amplitude of vibration perpendicular to the plane of the substrate, which serves as the reference vibrating motion for this gyroscope. A number of metallic (proof) masses are strategically positioned at the anti-node locations so that the effect of the Coriolis force can be used to sense the gyroscopic motion. Another unique feature of the device is that because the SAW device operates at RF frequencies, one could easily connect the IDT device to a microstrip antenna and read the acceleration and gyro rate remotely by wireless transmission and reception using the Bluetooth technology. This concept is proposed in this paper.

Proceedings Article | 21 November 2001 Paper

Micro stereo lithography and fabrication of 3D MEMS and their applications

Vijay Varadan, Vasundara Varadan

Proceedings Volume 4592, (2001) https://doi.org/10.1117/12.448953

KEYWORDS: Polymers, Ceramics, Microelectromechanical systems, Hydrogen, Ultraviolet radiation, Actuators, Silicon, Microfluidics, Lithography, Stereolithography

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Micro Stereo Lithography (MSL) is a poor man's LIGA for fabricating high aspect ratio MEMS devices in UV curable semiconducting polymers using either two computer-controlled low inertia galvanometric mirrors with the aid of focusing lens or an array of optical fibers. This technique has also been successfully used recently for fabricating 3D metallic and ceramic MEMS devices. Microfabrication techniques such as bulk micromachining and surface micromachining currently employed to conceive MEMS are largely derived from the standard IC and microelectronics technology. Even though many MEMS devices with integrated electronics have been achieved by using the traditional micromachining techniques, some limitations have nevertheless to be underlined: 1) these techniques are very expensive and need specific installations as well as a cleanroom environment, 2) the materials that can be used up to now are restricted to silicon and metals, 3) the manufacture of 3D parts having curved surfaces or an important number of layers is not possible. Moreover, for some biological applications, the materials used for sensors must be compatible with human body and the actuators need to have high strain and displacement which the current silicon based MEMS do not provide. It is thus natural for the researchers to look for alternative methods to make 3D sensors and actuators using polymeric based materials. For MSL techniques to be successful as their silicon counterparts, one has to come up with multifunctional polymers. These multifunctional polymers have not only a high sensing capability but also a high strain and actuation performance. With the invention of organic thin film transistor, now it seems possible to fabricate polymeric based MEMS devices with built-in- electronics. Moreover, with combined architecture techniques, one can integrate silicon devices with the polymeric ones without much difficulty. In this paper, the applications of MSL for polymer and ceramic based microstructures and MEMS and applications of these devices in conceiving a compact fuel cell with carbon nanotubes and hydrogen are discussed.

Proceedings Article | 21 November 2001 Paper

MEMS- and NEMS-based smart devices and systems

Vijay Varadan

Proceedings Volume 4591, (2001) https://doi.org/10.1117/12.449169

KEYWORDS: Polymers, Microelectromechanical systems, Sensors, Carbon, Actuators, Composites, Silicon, Nanoelectromechanical systems, Lithography, Carbon nanotubes

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The microelectronics industry has seen explosive growth during the last thirty years. Extremely large markets for logic and memory devices have driven the development of new materials, and technologies for the fabrication of even more complex devices with features sized now don at the sub micron and nanometer level. Recent interest has arisen in employing these materials, tools and technologies for the fabrication of miniature sensors and actuators and their integration with electronic circuits to produce smart devices and systems. This effort offers the promise of: 1) increasing the performance and manufacturability of both sensors and actuators by exploiting new batch fabrication processes developed including micro stereo lithographic an micro molding techniques; 2) developing novel classes of materials and mechanical structures not possible previously, such as diamond like carbon, silicon carbide and carbon nanotubes, micro-turbines and micro-engines; 3) development of technologies for the system level and wafer level integration of micro components at the nanometer precision, such as self-assembly techniques and robotic manipulation; 4) development of control and communication systems for MEMS devices, such as optical and RF wireless, and power delivery systems, etc. A novel composite structure can be tailored by functionalizing carbon nano tubes and chemically bonding them with the polymer matrix e.g. block or graft copolymer, or even cross-linked copolymer, to impart exceptional structural, electronic and surface properties. Bio- and Mechanical-MEMS devices derived from this hybrid composite provide a new avenue for future smart systems. The integration of NEMS (NanoElectroMechanical Systems), MEMS, IDTs (Interdigital Transducers) and required microelectronics and conformal antenna in the multifunctional smart materials and composites results in a smart system suitable for sensing and control of a variety functions in automobile, aerospace, marine and civil structures and food and medical industries. This unique combination of technologies also results in novel conformal sensors that can be remotely sensed by an antenna system with the advantage of no power requirements at the sensor site. This paper provides a brief review of MEMS and NEMS based smart systems for various applications mentioned above. Carbon Nano Tubes (CNT) with their unique structure, have already proven to be valuable in their application as tips for scanning probe microscopy, field emission devices, nanoelectronics, H₂-storage, electromagnetic absorbers, ESD, EMI films and coatings and structural composites. For many of these applications, highly purified and functionalized CNT which are compatible with many host polymers are needed. A novel microwave CVD processing technique to meet these requirements has been developed at Penn State Center for the engineering of Electronic and Acoustic Materials and Devices (CEEAMD). This method enables the production of highly purified carbon nano tubes with variable size (from 5-40 nm) at low cost (per gram) and high yield. Whereas, carbon nano tubes synthesized using the laser ablation or arc discharge evaporation method always include impurity due to catalyst or catalyst support. The Penn State research is based on the use of zeolites over other metal/metal oxides in the microwave field for a high production and uniformity of the product. An extended conventional purification method has been employed to purify our products in order to remove left over impurity. A novel composite structure can be tailored by functionalizing carbon nano tubes and chemically bonding them with the polymer matrix e.g. block or graft copolymer, or even cross- linked copolymer, to impart exceptional structural, electronic and surface properties. Bio- and Mechanical-MEMS devices derived from this hybrid composites will be presented.

Proceedings Article | 19 November 2001 Paper

Three-dimensional MEMS devices with functionalized carbon nanotubes

Vijay Varadan, Jining Xie, Taeksoo Ji

Proceedings Volume 4590, (2001) https://doi.org/10.1117/12.454595

KEYWORDS: Carbon nanotubes, Microelectromechanical systems, Polymers, Microwave radiation, Carbon, Chemical vapor deposition, Ultraviolet radiation, Bridges, Electronics, Composites

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Proceedings Article | 23 October 2001 Paper

MEMS- and NEMS-based complex adaptive smart devices and systems

Vijay Varadan

Proceedings Volume 4512, (2001) https://doi.org/10.1117/12.446770

KEYWORDS: Silicon, Polymers, Sensors, Microelectromechanical systems, Ceramics, Actuators, Micromachining, Acoustics, Etching, Lithography

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Proceedings Article | 21 August 2001 Paper

Rayleigh-Ritz formulation for active control of the acoustics in cabin enclosures

Senthil Gopinathan, Vasundara Varadan, Vijay Varadan

Proceedings Volume 4326, (2001) https://doi.org/10.1117/12.436507

KEYWORDS: Sensors, Acoustics, Actuators, Systems modeling, Motion models, Composites, Electrodes, Control systems, Control systems design, Finite element methods

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Proceedings Article | 16 August 2001 Paper

Optimized multilayered wideband absorbers with graded fractal FSS

K. Vinoy, K. Jose, Vijay Varadan, Vasundara Varadan

Proceedings Volume 4334, (2001) https://doi.org/10.1117/12.436597

KEYWORDS: Fractal analysis, Radar, Dielectrics, Multilayers, Genetic algorithms, Genetics, Analog electronics, Reflection, FSS based metamaterials, Optimization (mathematics)

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Proceedings Article | 16 August 2001 Paper

New type of silicon photoelectronic negative resistance devices: PDUBAT

Yanan Sha, Vijay Varadan, Vasundara Varadan, Shuyong Li, Weilian Guo, Yunguang Zheng

Proceedings Volume 4334, (2001) https://doi.org/10.1117/12.436624

KEYWORDS: Resistance, Diffusion, Oscillators, Transistors, Signal detection, Light emitting diodes, Silicon, Mechanics, Semiconductors, Modulation

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Proceedings Article | 16 August 2001 Paper

Small resonant fractal antennas

K. Vinoy, K. Jose, Vijay Varadan, Vasundara Varadan

Proceedings Volume 4334, (2001) https://doi.org/10.1117/12.436602

KEYWORDS: Antennas, Fractal analysis, Information operations, Numerical simulations, Dielectrics, Neodymium, Silicon, Smart materials, Electronics, Microelectromechanical systems

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Proceedings Article | 16 August 2001 Paper

Performance improvement of rf MEMS capacitive switches with high-dielectric-constant materials

Hargsoon Yoon, Yanan Sha, Pramod Sharma, K. Vinoy, Vijay Varadan, Vasundara Varadan

Proceedings Volume 4334, (2001) https://doi.org/10.1117/12.436618

KEYWORDS: Switches, Microelectromechanical systems, Copper, Dielectrics, Metals, Oxides, Electrodes, Capacitors, Platinum, Titanium

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Proceedings Article | 16 August 2001 Paper

Micro stereo lithography for 3D MEMS devices

Vijay Varadan, Vasundara Varadan

Proceedings Volume 4334, (2001) https://doi.org/10.1117/12.436612

KEYWORDS: Polymers, Ceramics, Microelectromechanical systems, Sensors, Ultraviolet radiation, Computer aided design, Lithography, Silicon, Stereolithography, Reflectors

Read Abstract +

Micro Stereo Lithography (MSL) is a poor man's LIGA for fabricating high aspect ratio MEMS devices in UV curable semiconducting polymers using either two computer-controlled low inertia galvanometric mirrors with the aid of focusing lens or an array of optical fibers. This technique has also been successfully used recently for fabricating 3D metallic and ceramic MEMS devices. Microfabrication techniques such as bulk micromachining and surface micromachining currently employed to conceive MEMS are largely derived from the standard IC and microelectronics technology. Even though many MEMS devices with integrated electronics have been achieved by using the traditional micromachining techniques, some limitations have nevertheless to be underlined: (1) these techniques are very expensive and need specific installations as well as a cleanroom environment, (2) the materials that can be used up to now are restricted to silicon and metals, (3) the manufacture of 3D parts having curved surfaces or an important number of layers is not possible. Moreover, for some biological applications, the materials used for sensors must be compatible with human body and the actuators need to have high strain and displacement which the current silicon based MEMS do not provide. It is thus natural for the researchers to 'look' for alternative methods to make 3D sensors and actuators using polymeric based materials. For MSL techniques to be successful as their silicon counterparts, one has to come up with multifunctional polymers. These multifunctional polymers have not only a high sensing capability but also a high strain and actuation performance. With the invention of organic thin film transistor, now it seems possible to fabricate polymeric based MEMS devices with built-in- electronics. Moreover, with combined architecture techniques, one can integrate silicon devices with the polymeric ones without much difficulty. In this paper, the applications of MSL for polymer and ceramic based microstructures and MEMS are discussed with some examples.

Proceedings Article | 16 August 2001 Paper

Design, simulation, and testing of wireless temperature sensor

William Suh, K. Jose, Vijay Varadan, Vasundara Varadan

Proceedings Volume 4334, (2001) https://doi.org/10.1117/12.436608

KEYWORDS: Sensors, Temperature metrology, Reflectors, Antennas, Temperature sensors, Phase measurement, Calibration, Acoustics, Wave sensors, Modulation

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Proceedings Article | 16 August 2001 Paper

Hybrid MEMS-IDT-based accelerometer and gyroscope in a single chip

Vijay Varadan, William Suh, K. Jose, Vasundara Varadan

Proceedings Volume 4334, (2001) https://doi.org/10.1117/12.436591

KEYWORDS: Gyroscopes, Reflectors, Sensors, Acoustics, Antennas, Amplifiers, Phase shifts, Silicon, Semiconducting wafers, Oscillators

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Proceedings Article | 16 August 2001 Paper

Design, simulation, and testing of IDT-based MEMS gyroscope

William Suh, K. Jose, Pascal Xavier, Vijay Varadan, Vasundara Varadan

Proceedings Volume 4334, (2001) https://doi.org/10.1117/12.436589

KEYWORDS: Gyroscopes, Resonators, Acoustics, Sensors, Microelectromechanical systems, Reflectors, Particles, Wave propagation, Transducers, Circuit switching

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Proceedings Article | 16 August 2001 Paper

Micromachined systems for rf and microwave antenna applications

K. Vinoy, Pramod Sharma, K. Jose, Vijay Varadan, Vasundara Varadan

Proceedings Volume 4334, (2001) https://doi.org/10.1117/12.436595

KEYWORDS: Switches, Microelectromechanical systems, Phase shifts, Microwave radiation, Antennas, Capacitors, Dielectrics, Capacitance, Thin films, Extremely high frequency

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Proceedings Article | 30 April 2001 Paper

Wireless surface acoustic wave and MEMS-based microsensors

Vijay Varadan, Vasundara Varadan

Proceedings Volume 4407, (2001) https://doi.org/10.1117/12.425310

KEYWORDS: Sensors, Reflectors, Acoustics, Gyroscopes, Antennas, Microelectromechanical systems, Polymers, Fermium, Frequency modulation, Silicon

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Proceedings Article | 30 April 2001 Paper

Micro stereo lithography for fabrication of 3D polymeric and ceramic MEMS

Vijay Varadan, Vasundara Varadan

Proceedings Volume 4407, (2001) https://doi.org/10.1117/12.425296

KEYWORDS: Polymers, Ceramics, Microelectromechanical systems, Ultraviolet radiation, Computer aided design, Lithography, Resistance, Stereolithography, Actuators, Silicon

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Proceedings Article | 21 March 2001 Paper

Closed-loop finite element modeling of smart structures: an overview

Vasundara Varadan, Senthil Gopinathan, Woosuk Chang, Vijay Varadan

Proceedings Volume 4235, (2001) https://doi.org/10.1117/12.420863

KEYWORDS: Sensors, Actuators, Performance modeling, Smart structures, Finite element methods, Control systems, Matrices, Interference (communication), RGB color model, Feedback control

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Proceedings Article | 16 March 2001 Paper

Highly sensitive and wide-dynamic-range navigation microsystem on a single chip

Vijay Varadan, K. Jose, Vasundara Varadan

Proceedings Volume 4236, (2001) https://doi.org/10.1117/12.418750

KEYWORDS: Microsystems

Proceedings Article | 16 March 2001 Paper

Application of MEMS in microwave and millimeter wave systems

Vijay Varadan, K. Vinoy, Hargsoon Yoon, K. Jose, Vasundara Varadan

Proceedings Volume 4236, (2001) https://doi.org/10.1117/12.418756

KEYWORDS: Microelectromechanical systems, Microwave radiation, Extremely high frequency

Proceedings Article | 16 March 2001 Paper

Directions for rf-controlled intelligent microvalve

Stefan Enderling, Vijay Varadan, Derek Abbott

Proceedings Volume 4236, (2001) https://doi.org/10.1117/12.418777

KEYWORDS: Acoustics, Wireless communications, Wave propagation, Actuators, Flow cytometry

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Proceedings Article | 16 March 2001 Paper

Design and development of passive MEMS-IDT sensors for continuous monitoring of tire pressure

Vijay Varadan, K. Jose, Vasundara Varadan

Proceedings Volume 4236, (2001) https://doi.org/10.1117/12.418762

KEYWORDS: Sensors

Proceedings Article | 16 March 2001 Paper

RF MEMS and reconfigurable conformal fractal antennas

Vijay Varadan, K. Vinoy, Vasundara Varadan

Proceedings Volume 4236, (2001) https://doi.org/10.1117/12.418758

KEYWORDS: Microelectromechanical systems, Fractal analysis, Antennas

Proceedings Article | 6 July 2000 Paper

Wireless IDT microsensors for subsurface sensing

Vasundara Varadan, Anikumar Tellakula, Richard Hollinger, Chun-Te Li, Vijay Varadan

Proceedings Volume 4129, (2000) https://doi.org/10.1117/12.390633

KEYWORDS: Sensors, Humidity, Microsensors, Antennas, Transceivers, Temperature metrology, Reflectors, Microelectromechanical systems, Passive sensors, Fermium

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Proceedings Article | 6 July 2000 Paper

Automated spot-by-spot inspection of arbitrary curved dielectric structures for quality and process control

Richard Hollinger, Vasundara Varadan, Anikumar Tellakula, K. Jose, Vijay Varadan

Proceedings Volume 4129, (2000) https://doi.org/10.1117/12.390635

KEYWORDS: Dielectrics, Antennas, Inspection, Reflection, Microwave radiation, Process control, Nondestructive evaluation, Free space, Composites, Manufacturing

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Proceedings Article | 6 July 2000 Paper

Noncontact broadband microwave material characterization at low and high temperatures

K. Jose, Vasundara Varadan, Richard Hollinger, Anikumar Tellakula, Vijay Varadan

Proceedings Volume 4129, (2000) https://doi.org/10.1117/12.390629

KEYWORDS: Temperature metrology, Dielectrics, Antennas, Free space, Microwave radiation, Material characterization, Quartz, Waveguides, Calibration, Metals

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Proceedings Article | 21 June 2000 Paper

Conformal fractal antenna and FSS for low-RCS applications

Vijay Varadan, K. Vinoy, K. Jose, Vasundara Varadan

Proceedings Volume 3990, (2000) https://doi.org/10.1117/12.388892

KEYWORDS: Antennas, Fractal analysis, Radar, FSS based metamaterials, Dielectrics, Reflection, Backscatter, Missiles, Aerodynamics, Dielectric filters

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Proceedings Article | 21 June 2000 Paper

Semiconductor polymer-based rf MEMS and its applications to microwave systems

Vijay Varadan, K. Jose, K. Vinoy, Vasundara Varadan

Proceedings Volume 3990, (2000) https://doi.org/10.1117/12.388921

KEYWORDS: Polymers, Microelectromechanical systems, Antennas, Phase shifts, Switches, Dielectrics, Microwave radiation, Capacitance, Phased arrays, Semiconductors

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Proceedings Article | 21 June 2000 Paper

Conformal and embedded IDT microsensors for health monitoring of structures

Vijay Varadan, Vasundara Varadan

Proceedings Volume 3990, (2000) https://doi.org/10.1117/12.388897

KEYWORDS: Sensors, Microelectromechanical systems, Microsensors, Transducers, Nondestructive evaluation, Antennas, Gyroscopes, Acoustics, Wave propagation, Wave plates

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Proceedings Article | 21 June 2000 Paper

Conformal and reconfigurable fractal antennas

K. Vinoy, K. Jose, Vijay Varadan, Vasundara Varadan

Proceedings Volume 3990, (2000) https://doi.org/10.1117/12.388891

KEYWORDS: Antennas, Fractal analysis, Dielectrics, Conformal antenna, Skin, Beam shaping, Microelectromechanical systems, Sensors, Satellites, Microactuators

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Proceedings Article | 21 June 2000 Paper

Micropump and venous valve by micro stereo lithography

Vijay Varadan, Vasundara Varadan

Proceedings Volume 3990, (2000) https://doi.org/10.1117/12.388901

KEYWORDS: Polymers, Microelectromechanical systems, Lithography, Ultraviolet radiation, Silicon, Stereolithography, Manufacturing, Actuators, Resistance, Microfluidics

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Proceedings Article | 21 June 2000 Paper

Deicing of helicopter blades using piezoelectric actuators

Srinivasa Ramanathan, Vasundara Varadan, Vijay Varadan

Proceedings Volume 3990, (2000) https://doi.org/10.1117/12.388906

KEYWORDS: Actuators, Adhesives, Aluminum, Interfaces, Sensors, Particles, Wave propagation, Wave plates, Liquids, Electrodes

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Proceedings Article | 21 June 2000 Paper

Solid state MOSFET-based hydrophone

Bei Zhu, J. Zhang, Vijay Varadan, Vasundara Varadan

Proceedings Volume 3990, (2000) https://doi.org/10.1117/12.388918

KEYWORDS: Ferroelectric polymers, Field effect transistors, Acoustics, Transducers, Capacitance, Silicon, Solid state electronics, Polymers, Ceramics, Oxides

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Proceedings Article | 21 June 2000 Paper

Conformal MEMS-IDT gyroscopes and their comparison with fiber optic gyro

Vijay Varadan, K. Jose, Pascal Xavier, D. Suh, Vasundara Varadan

Proceedings Volume 3990, (2000) https://doi.org/10.1117/12.388911

KEYWORDS: Gyroscopes, Microelectromechanical systems, Resonators, Acoustics, Wave propagation, Reflectors, Sensors, Fiber optic gyroscopes, Particles, Navigation systems

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Proceedings Article | 19 June 2000 Paper

Natural frequencies of a smart plate with segmented piezoelectric patches

Senthil Gopinathan, Vasundara Varadan, Vijay Varadan

Proceedings Volume 3984, (2000) https://doi.org/10.1117/12.388791

KEYWORDS: Actuators, Sensors, Motion models, Electrodes, Ferroelectric materials, Ferroelectric polymers, Silicon, Control systems design, Aluminum, Electronics engineering

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Proceedings Article | 19 June 2000 Paper

Finite element/boundary element simulation of interior noise control using active-passive control technique

Senthil Gopinathan, Vasundara Varadan, Vijay Varadan

Proceedings Volume 3984, (2000) https://doi.org/10.1117/12.388767

KEYWORDS: Acoustics, Sensors, Control systems, Actuators, Chemical elements, Feedback control, Control systems design, Interfaces, Foam, Systems modeling

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Proceedings Article | 29 September 1999 Paper

Semiconductor-polymer-based rf MEMS

Vijay Varadan, Vasundara Varadan, K. Jose

Proceedings Volume 3891, (1999) https://doi.org/10.1117/12.364448

KEYWORDS: Polymers, Phase shifts, Microelectromechanical systems, Antennas, Dielectrics, Electroactive polymers, Semiconductors, Electrodes, Capacitance, Phased arrays

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Proceedings Article | 29 September 1999 Paper

MEMS-IDT-based microaccelerometers and gyroscopes

Vijay Varadan, Vasundara Varadan

Proceedings Volume 3891, (1999) https://doi.org/10.1117/12.364475

KEYWORDS: Sensors, Gyroscopes, Antennas, Reflectors, Microelectromechanical systems, Silicon, Acoustics, Amplifiers, Fabrication, Phase shifts

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Proceedings Article | 2 September 1999 Paper

Wireless electro-optic switching network for optical fiber sensor array using MEMS-IDT devices

Vijay Varadan, Vasundara Varadan

Proceedings Volume 3878, (1999) https://doi.org/10.1117/12.361254

KEYWORDS: Reflectors, Switches, Electro optics, Antennas, Lithium niobate, Sensors, Fiber optics sensors, Optical arrays, Control systems, Switching

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Proceedings Article | 31 August 1999 Paper

Wireless surface-acoustic-wave-based humidity sensor

Richard Hollinger, Anikumar Tellakula, C.-T. Li, Vasundara Varadan, Vijay Varadan

Proceedings Volume 3876, (1999) https://doi.org/10.1117/12.360509

KEYWORDS: Sensors, Humidity, Reflectors, Antennas, Fermium, Frequency modulation, Transceivers, Acoustics, Phase shifts, Lithium niobate

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Proceedings Article | 31 August 1999 Paper

Micro stereo lithography and fabrication of 3D microdevices

Vijay Varadan, Vasundara Varadan

Proceedings Volume 3879, (1999) https://doi.org/10.1117/12.360516

KEYWORDS: Polymers, Microelectromechanical systems, Lithography, Ultraviolet radiation, Diffusers, Silicon, Computer aided design, Resistance, Mirrors, Microfluidics

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Proceedings Article | 31 August 1999 Paper

Programmable micro accelerometers and gyroscopes

Vijay Varadan, Vasundara Varadan

Proceedings Volume 3876, (1999) https://doi.org/10.1117/12.360484

KEYWORDS: Sensors, Gyroscopes, Reflectors, Antennas, Microelectromechanical systems, Transducers, Wave propagation, Acoustics, Amplifiers, Silicon

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Proceedings Article | 20 July 1999 Paper

Microsensors and MEMS for health monitoring of composite and aircraft structures in flight

Vijay Varadan, Vasundara Varadan

Proceedings Volume 3673, (1999) https://doi.org/10.1117/12.354290

KEYWORDS: Sensors, Microsensors, Microelectromechanical systems, Nondestructive evaluation, Electronics, Aircraft structures, Composites, Transducers, Acoustic emission, Antennas

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Proceedings Article | 20 July 1999 Paper

Design and development of 150-MHz wireless telemetry system for MEMS-IDT-based sensor

D. Piscotty, K. Jose, Vasundara Varadan, Vijay Varadan

Proceedings Volume 3673, (1999) https://doi.org/10.1117/12.354262

KEYWORDS: Antennas, Sensors, Crystals, Transmitters, Signal detection, Acoustics, Signal attenuation, Signal processing, Receivers, Transducers

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Proceedings Article | 20 July 1999 Paper

Love-wave-based ice sensor

Sunil Gangadaran, Vasundara Varadan, Vijay Varadan, K. Jose, Massood Atashbar

Proceedings Volume 3673, (1999) https://doi.org/10.1117/12.354279

KEYWORDS: Sensors, Acoustics, Wave sensors, Liquids, Wave propagation, Silica, Plasma enhanced chemical vapor deposition, Polarization, Quartz, Dielectrics

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Proceedings Article | 20 July 1999 Paper

MEMS-IDT-based accelerometers and gyroscopes

Vijay Varadan, Pascal Xavier, Vasundara Varadan, D. Suh, Massood Atashbar, K. Jose

Proceedings Volume 3673, (1999) https://doi.org/10.1117/12.354267

KEYWORDS: Sensors, Gyroscopes, Antennas, Reflectors, Microelectromechanical systems, Acoustics, Transducers, Silicon, Wave propagation, Amplifiers

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Proceedings Article | 20 July 1999 Paper

Smart tongue and nose

Vijay Varadan, Julian Gardner

Proceedings Volume 3673, (1999) https://doi.org/10.1117/12.354281

KEYWORDS: Sensors, Nose, Liquids, Tongue, Signal attenuation, Antennas, Oscillators, Wave propagation, Semiconducting wafers, Reflectors

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Proceedings Article | 20 July 1999 Paper

Tunable and electronically steerable microstrip antenna

K. Jose, Vijay Varadan, Vasundara Varadan

Proceedings Volume 3673, (1999) https://doi.org/10.1117/12.354269

KEYWORDS: Antennas, Dielectrics, Microwave radiation, Phase shifts, Magnetism, Barium, Strontium, Sol-gels, Integrated circuit design, Integrated circuits

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Proceedings Article | 9 June 1999 Paper

Active and passive noise control using electroactive polymer actuators (EAPAs)

Kartik Ramanathan, Bei Zhu, Woosuk Chang, Vasundara Varadan, Vijay Varadan

Proceedings Volume 3668, (1999) https://doi.org/10.1117/12.350704

KEYWORDS: Actuators, Electroactive polymers, Silicon, Polymers, Electrodes, Acoustics, Biomedical optics, Transparency, Gold, Control systems

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Proceedings Article | 4 June 1999 Paper

Vibration and noise control using an optimal output feedback controller

Young-Hun Lim, Senthil Gopinathan, Vasundara Varadan, Vijay Varadan

Proceedings Volume 3667, (1999) https://doi.org/10.1117/12.350092

KEYWORDS: Actuators, Sensors, Feedback control, Control systems, Vibration control, Solids, 3D modeling, Matrices, Smart structures, Acoustics

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Proceedings Article | 4 June 1999 Paper

Detailed study of electromechanical fields in piezolaminates

Senthil Gopinathan, Vasundara Varadan, Vijay Varadan

Proceedings Volume 3667, (1999) https://doi.org/10.1117/12.350095

KEYWORDS: Sensors, Actuators, Interfaces, 3D modeling, Composites, Electric field sensors, Ferroelectric materials, Vibration control, Chemical elements, Electrodes

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Proceedings Article | 4 June 1999 Paper

Robust, compact, and inexpensive analog controllers for cabin noise control

Woosuk Chang, Kartik Ramanathan, Vasundara Varadan, Vijay Varadan

Proceedings Volume 3667, (1999) https://doi.org/10.1117/12.350104

KEYWORDS: Analog electronics, Sensors, Actuators, Acoustics, Device simulation, Interference (communication), Vibration control, Modal analysis, Mathematical modeling, Ferroelectric materials

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Proceedings Article | 4 February 1999 Paper

In-situ microwave characterization of planar/nonplanar specimens

Vasundara Varadan, K. Jose, Vijay Varadan

Proceedings Volume 3589, (1999) https://doi.org/10.1117/12.339950

KEYWORDS: Microwave radiation, Nondestructive evaluation, Free space, Antennas, Dielectrics, Composites, Inspection, Manufacturing, Glasses, Metals

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Proceedings Article | 4 February 1999 Paper

In-situ noncontact nondestructive point-to-point microwave inspection system

Vasundara Varadan, Richard Hollinger, Anikumar Tellakula, K. Jose, Vijay Varadan

Proceedings Volume 3589, (1999) https://doi.org/10.1117/12.339951

KEYWORDS: Antennas, Microwave radiation, Inspection, Dielectrics, Phase measurement, Nondestructive evaluation, Network security, Process control, Manufacturing, Control systems

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Proceedings Article | 24 July 1998 Paper

Radiated noise control via structural vibration control

Vasundara Varadan, Senthil Gopinathan, Young-Hun Lim, Vijay Varadan

Proceedings Volume 3323, (1998) https://doi.org/10.1117/12.316334

KEYWORDS: Sensors, Actuators, Acoustics, Vibration control, Chemical elements, Feedback control, Electrodes, Active vibration control, Gadolinium, Transition metals

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Proceedings Article | 20 July 1998 Paper

Smart programmable wireless microaccelerometers

Vijay Varadan, Hareesh Subramanian, Vasundara Varadan

Proceedings Volume 3328, (1998) https://doi.org/10.1117/12.320186

KEYWORDS: Sensors, Reflectors, Antennas, Silicon, Phase shifts, Acoustics, Metals, Semiconducting wafers, Control systems, Oxides

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Proceedings Article | 20 July 1998 Paper

Micromachined wet cell for a Love-wave liquid sensor

Scott Curtin, Bernhard Jakoby, Axel Berthold, Vijay Varadan, Vasundara Varadan, Michael Vellekoop

Proceedings Volume 3328, (1998) https://doi.org/10.1117/12.320170

KEYWORDS: Liquids, Sensors, Silicon, Semiconducting wafers, Photomasks, Etching, Acoustics, Wave propagation, Transducers, Aluminum

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Proceedings Article | 20 July 1998 Paper

IDT sensors for detection of ice on rotorcraft

Vasundara Varadan, Vijay Varadan, Xiao-Qi Bao

Proceedings Volume 3328, (1998) https://doi.org/10.1117/12.320197

KEYWORDS: Sensors, Antennas, Liquids, Telecommunications, Signal attenuation, Reflectors, Oscillators, Transducers, Semiconducting wafers, Wave propagation

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Proceedings Article | 16 April 1998 Paper

Dynamical finite element models for MEMS and smart structures

Vasundara Varadan, Young-Hun Lim, Vijay Varadan

Proceedings Volume 3321, (1998) https://doi.org/10.1117/12.305618

KEYWORDS: Actuators, Sensors, Finite element methods, Microelectromechanical systems, Smart structures, Ferroelectric materials, 3D modeling, Instrument modeling, Ferroelectric polymers, Feedback control

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Proceedings Article | 16 April 1998 Paper

MEMS for measuring deflection, acceleration, and ice sensing on rotorcraft

Vijay Varadan, Vasundara Varadan

Proceedings Volume 3321, (1998) https://doi.org/10.1117/12.305612

KEYWORDS: Sensors, Microelectromechanical systems, Antennas, Reflectors, Actuators, Semiconducting wafers, Telecommunications, Remote sensing, Microsensors, Fermium

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Proceedings Article | 14 November 1997 Paper

Design and fabrication of wireless remotely readable MEMS accelerometers

Vijay Varadan, Hareesh Subramanian, Vasundara Varadan

Proceedings Volume 3242, (1997) https://doi.org/10.1117/12.293537

KEYWORDS: Reflectors, Sensors, Antennas, Silicon, Reflection, Phase shifts, Microelectromechanical systems, Acoustics, Control systems, Metals

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Proceedings Article | 19 June 1997 Paper

Design and development of smart skin conformal antenna with MEMS structural sensors and actuators

Vijay Varadan, Vasundara Varadan

Proceedings Volume 3046, (1997) https://doi.org/10.1117/12.276632

KEYWORDS: Antennas, Phase shifts, Skin, Sensors, Microelectromechanical systems, Dielectrics, Actuators, Radar, Electromagnetism, Beam steering

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Proceedings Article | 19 June 1997 Paper

Wireless remotely readable microaccelerometer

Hareesh Subramanian, Vasundara Varadan, Vijay Varadan

Proceedings Volume 3046, (1997) https://doi.org/10.1117/12.276611

KEYWORDS: Sensors, Silicon, Acoustics, Lithium niobate, Phase shifts, Microelectromechanical systems, Antennas, Control systems, Microelectronics, Reflectors

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Proceedings Article | 19 June 1997 Paper

IDT, SAW, and MEMS sensors for measuring deflection, acceleration, and ice detection of aircraft

Vijay Varadan, Vasundara Varadan, Xiao-Qi Bao

Proceedings Volume 3046, (1997) https://doi.org/10.1117/12.276610

KEYWORDS: Sensors, Microelectromechanical systems, Antennas, Semiconducting wafers, Reflectors, Actuators, Telecommunications, Remote sensing, Silicon, Fermium

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Proceedings Article | 19 June 1997 Paper

ASIC chips and their integration to smart devices

Neranjen Ramalingam, Vijay Varadan, Vasundara Varadan

Proceedings Volume 3046, (1997) https://doi.org/10.1117/12.276615

KEYWORDS: Clocks, Real-time computing, Multiplexers, Frequency conversion, Laminated object manufacturing, Signal processing, Adaptive optics, Logic, Time metrology, Signal generators

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Proceedings Article | 13 June 1997 Paper

Closed-loop finite element modeling of active/passive damping in structural vibration control

Young-Hun Lim, Vasundara Varadan, Vijay Varadan

Proceedings Volume 3039, (1997) https://doi.org/10.1117/12.276530

KEYWORDS: Actuators, Sensors, Feedback control, 3D modeling, Control systems, Finite element methods, Vibration control, Aluminum, Smart structures, Matrices

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Proceedings Article | 23 September 1996 Paper

MEMS for measuring deflection and deicing of helicopter rotors

Vasundara Varadan, Vijay Varadan, X. Q. Bao

Proceedings Volume 2881, (1996) https://doi.org/10.1117/12.251247

KEYWORDS: Sensors, Microelectromechanical systems, Antennas, Actuators, Semiconducting wafers, Reflectors, Remote sensing, Telecommunications, Silicon, Transducers

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Proceedings Article | 17 September 1996 Paper

Innovative frequency measurement technique used in the design of a single channel frequency to digital converter ASIC

Neranjen Ramalingam, Vijay Varadan, Vasundara Varadan

Proceedings Volume 2882, (1996) https://doi.org/10.1117/12.250718

KEYWORDS: Transducers, Digital electronics, Application specific integrated circuits, Clocks, Defense technologies, Ranging, Sensors, Smart sensors

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Proceedings Article | 31 May 1996 Paper

Finite element modeling of active noise control with optimal placement of multiple actuators

Jae-Wan Kim, Vasundara Varadan, Vijay Varadan

Proceedings Volume 2715, (1996) https://doi.org/10.1117/12.240800

KEYWORDS: Actuators, Acoustics, 3D modeling, Finite element methods, Solids, Transition metals, Instrument modeling, Bessel functions, Ferroelectric materials, Denoising

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Proceedings Article | 31 May 1996 Paper

Finite element modeling of the transient response of smart structures

Young-Hun Lim, Vasundara Varadan, Vijay Varadan

Proceedings Volume 2715, (1996) https://doi.org/10.1117/12.240802

KEYWORDS: Sensors, Smart structures, Finite element methods, Chemical elements, Actuators, Ceramics, Aluminum, Transition metals, Instrument modeling, Numerical simulations

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Proceedings Article | 20 May 1996 Paper

Design and development of conformal smart spiral antenna

Vijay Varadan, Vasundara Varadan

Proceedings Volume 2722, (1996) https://doi.org/10.1117/12.240428

KEYWORDS: Antennas, Dielectrics, Linear filtering, Composites, Multilayers, Coating, Skin, Phase measurement, Conformal antenna, Transducers

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Proceedings Article | 20 May 1996 Paper

Integration of interdigital transducers, MEMS, and antennas for smart structures

Vijay Varadan, Vasundara Varadan, Xiao-Qi Bao

Proceedings Volume 2722, (1996) https://doi.org/10.1117/12.240433

KEYWORDS: Sensors, Antennas, Microelectromechanical systems, Actuators, Reflectors, Polymers, Semiconducting wafers, Transducers, Electronics, Remote sensing

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Proceedings Article | 20 May 1996 Paper

Smart Plates for noise reduction using MEMS technology

Vasundara Varadan, Vijay Varadan, Xiao-Qi Bao

Proceedings Volume 2722, (1996) https://doi.org/10.1117/12.240448

KEYWORDS: Sensors, Microelectromechanical systems, Actuators, Acoustics, Ferroelectric materials, Aluminum, Control systems, Denoising, Silicon, Polonium

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Proceedings Article | 20 May 1996 Paper

Three-dimensional polymeric and ceramic MEMS and their applications

Vijay Varadan, Vasundara Varadan, S. Motojima

Proceedings Volume 2722, (1996) https://doi.org/10.1117/12.240440

KEYWORDS: Polymers, Microelectromechanical systems, Electromagnetism, Coating, Absorption, Ultraviolet radiation, Ceramics, Ferroelectric polymers, Chemical vapor deposition, Dielectrics

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Proceedings Article | 15 September 1995 Paper

Finite element modeling of the dynamic response of a MEMS sensor

Young-Hun Lim, Vasundara Varadan, Vijay Varadan

Proceedings Volume 2642, (1995) https://doi.org/10.1117/12.221173

KEYWORDS: Sensors, Microelectromechanical systems, Finite element methods, Ferroelectric materials, Ceramics, Aluminum, Transition metals, Actuators, 3D modeling, Dielectrics

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Proceedings Article | 15 September 1995 Paper

Smart electronics and MEMS for aerospace structures

Vijay Varadan, Vasundara Varadan

Proceedings Volume 2642, (1995) https://doi.org/10.1117/12.221165

KEYWORDS: Antennas, Microelectromechanical systems, Polymers, Sensors, Electronics, Skin, Actuators, Aerospace engineering, Particles, Ceramics

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Proceedings Article | 26 May 1995 Paper

Stripline microwave phase shifter on tunable substrate

Vijay Varadan, Vasundara Varadan, K. Jose, Ronald Hughes

Proceedings Volume 2448, (1995) https://doi.org/10.1117/12.210465

KEYWORDS: Phase shifts, Microwave radiation, Phased arrays, Dielectrics, Antennas, PIN photodiodes, Electronic filtering, Dielectric filters, Polymers, Network security

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Proceedings Article | 26 May 1995 Paper

Microstrip antenna on tunable substrate

K. Jose, Vijay Varadan, Vasundara Varadan, P. Mohanan

Proceedings Volume 2448, (1995) https://doi.org/10.1117/12.210478

KEYWORDS: Antennas, Dielectrics, Microwave radiation, Magnetism, Electronics, Sol-gels, Thin films, Barium, Strontium, Integrated circuit design

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Proceedings Article | 26 May 1995 Paper

Smart electronics with interdigital electrodes, antennas, and MEMS for aerospace structures

Vijay Varadan, Vasundara Varadan

Proceedings Volume 2448, (1995) https://doi.org/10.1117/12.210455

KEYWORDS: Antennas, Polymers, Microelectromechanical systems, Sensors, Actuators, Ferroelectric polymers, Skin, Ceramics, Particles, Electronics

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Proceedings Article | 26 May 1995 Paper

Smart skin spiral antenna with chiral absorber

Vijay Varadan, Vasundara Varadan

Proceedings Volume 2448, (1995) https://doi.org/10.1117/12.210479

KEYWORDS: Antennas, Dielectrics, Skin, Electromagnetism, Composites, Radar, Conformal antenna, Multiple scattering, Spherical lenses, Interfaces

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Proceedings Article | 26 May 1995 Paper

Smart electronics and sensors for IVHS and automobile collision warning antenna systems

Vijay Varadan, Vasundara Varadan

Proceedings Volume 2448, (1995) https://doi.org/10.1117/12.210475

KEYWORDS: Antennas, Sensors, Bridges, Phase shifts, Electronics, Dielectrics, Polymers, Beam steering, Ceramics, Electrodes

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Proceedings Article | 8 May 1995 Paper

Crack detection in fastener holes using surface acoustic wave

Xiao-Qi Bao, Vasundara Varadan, Vijay Varadan

Proceedings Volume 2443, (1995) https://doi.org/10.1117/12.208269

KEYWORDS: Acoustics, Wave plates, Transducers, Ultrasonics, Structural health monitoring, Electrodes, Aluminum, Reflection, Mechanical engineering, Sensors

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Proceedings Article | 5 May 1995 Paper

Modeling of sensor fidelity

Vasundara Varadan, Jae-Wan Kim, Vijay Varadan

Proceedings Volume 2442, (1995) https://doi.org/10.1117/12.208866

KEYWORDS: Sensors, Chemical elements, Ferroelectric materials, Interfaces, Epoxies, Solids, Mathematical modeling, Finite element methods, Polymers, Acoustics

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Proceedings Article | 5 May 1995 Paper

Optimal design of enclosures for active noise control and isolation

Vasundara Varadan, Jae-Wan Kim, Vijay Varadan

Proceedings Volume 2442, (1995) https://doi.org/10.1117/12.208864

KEYWORDS: Actuators, Acoustics, Ferroelectric materials, Finite element methods, 3D modeling, Sensors, Transducers, Electrodes, Vibration control, Bessel functions

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Proceedings Article | 5 May 1995 Paper

FEM modeling of infinite/semi-infinite domains by using slope constraint and drilling degrees of freedom (d.o.f.)

Jae-Wan Kim, Vasundara Varadan, Vijay Varadan

Proceedings Volume 2442, (1995) https://doi.org/10.1117/12.208840

KEYWORDS: Chemical elements, Finite element methods, Mathematical modeling, Acoustics, Linear elements, Scattering, Solids, Smart structures, Electromagnetism, Electromagnetic scattering

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Proceedings Article | 13 September 1994 Paper

Global and local health monitoring of civil structures using smart ferroelectric sensors and electronically steerable antennas

Vijay Varadan, Vasundara Varadan

Proceedings Volume 2361, (1994) https://doi.org/10.1117/12.184824

KEYWORDS: Antennas, Sensors, Polymeric sensors, Polymers, Transducers, Ceramics, Electrodes, Phase shifts, Waveguides, Telecommunications

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Proceedings Article | 1 May 1994 Paper

Active noise control using piezoelectric actuator for a machine

Xiao-Qi Bao, Zoubeida Ounaies, Vijay Varadan, Vasundara Varadan

Proceedings Volume 2189, (1994) https://doi.org/10.1117/12.174058

KEYWORDS: Actuators, Sensors, Ferroelectric materials, Control systems, Analog electronics, Aluminum, Optical sensors, Phase shifts, Software, Interference (communication)

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Proceedings Article | 1 May 1994 Paper

Multilayer tunable ferroelectric materials and thin films

Vijay Varadan, Vasundara Varadan, Fathi Selmi, Zoubeida Ounaies, K. Jose

Proceedings Volume 2189, (1994) https://doi.org/10.1117/12.174080

KEYWORDS: Microwave radiation, Multilayers, Thin films, Ceramics, Dielectrics, Sol-gels, Plasma, Strontium, Ferroelectric materials, Barium

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Proceedings Article | 1 May 1994 Paper

Elimination of background clutter in airports for instrument landing systems

K. Jose, Vijay Varadan, Vasundara Varadan

Proceedings Volume 2189, (1994) https://doi.org/10.1117/12.174054

KEYWORDS: Specular reflections, Dielectrics, Reflection, Dielectric polarization, Buildings, Antennas, Reflectors, Mechanics, Metals, Constructive interference

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Proceedings Article | 1 May 1994 Paper

Active absorption of acoustic wave using state-space control approach

Zhen Wu, Vijay Varadan, Vasundara Varadan, Kwang Lee

Proceedings Volume 2189, (1994) https://doi.org/10.1117/12.174059

KEYWORDS: Control systems, Acoustics, Absorption, Sensors, Feedback control, Actuators, Systems modeling, Computer simulations, Reflection, Error analysis

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Proceedings Article | 1 May 1994 Paper

Long-wavelength models for effectively chiral and achiral microwave composites containing chiral inclusions

Vasundara Varadan, R. Apparao, Vijay Varadan

Proceedings Volume 2192, (1994) https://doi.org/10.1117/12.174236

KEYWORDS: Composites, Data modeling, Microwave radiation, Dielectrics, Multiple scattering, Polarizability, Magnetism, Particles, Wave propagation, Terbium

Read Abstract +

Proceedings Article | 1 May 1994 Paper

Finite element modeling of a finite piezoelectric sensor/actuator embedded in a fluid-loaded plate

Jae-Wan Kim, Vasundara Varadan, Vijay Varadan

Proceedings Volume 2192, (1994) https://doi.org/10.1117/12.174220

KEYWORDS: Sensors, Wave plates, Chemical elements, Solids, Finite element methods, Actuators, Ferroelectric materials, Acoustics, Transducers, Mathematical modeling

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Proceedings Article | 1 May 1994 Paper

Sol-gel and microwave processing of PZT materials for sensor and actuator applications

Zoubeida Ounaies, Vijay Varadan, Vasundara Varadan

Proceedings Volume 2189, (1994) https://doi.org/10.1117/12.174078

KEYWORDS: Microwave radiation, Ferroelectric materials, Sol-gels, Ceramics, Actuators, Particles, Dielectrics, Lead, Sensors, Strontium

Read Abstract +

Proceedings Article | 1 May 1994 Paper

Electronically steerable millimeter-wave antennas

Vijay Varadan, Vasundara Varadan, K. Jose, James Kelly

Proceedings Volume 2189, (1994) https://doi.org/10.1117/12.174053

KEYWORDS: Antennas, Dielectrics, Waveguides, Phase shifts, Beam steering, Ceramics, Metals, Magnetism, Extremely high frequency, Thin films

Read Abstract +

Proceedings Article | 1 May 1994 Paper

Prediction of modal responses for optimal selection of actuator positions in rectangular plate

Suk-Yoon Hong, Vasundara Varadan, Vijay Varadan

Proceedings Volume 2189, (1994) https://doi.org/10.1117/12.174055

KEYWORDS: Actuators, Control systems, Sensors, Vibration control, Distributed computing, Matrices, Feedback control, Computer simulations, Computing systems, LCDs

Read Abstract +

Proceedings Article | 23 July 1993 Paper

Sol-gel processing and automation of tunable ceramic materials

Fathi Selmi, Vasundara Varadan, B. Herner, Vijay Varadan

Proceedings Volume 1916, (1993) https://doi.org/10.1117/12.148497

KEYWORDS: Ceramics, Oxides, Carbonates, Microwave radiation, Dielectrics, Zirconium dioxide, Plasma systems, Strontium, X-ray diffraction, Iron

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Proceedings Article | 23 July 1993 Paper

UV-curable EMI-shielding conformal coatings on printed circuit boards

J. Terosky, Vijay Varadan, Vasundara Varadan

Proceedings Volume 1916, (1993) https://doi.org/10.1117/12.148476

KEYWORDS: Electromagnetic coupling, Electromagnetism, Electronic components, Electromagnetic interference, Ultraviolet radiation, Network security, Analog electronics, Calibration, Digital electronic circuits, Electronics engineering

Read Abstract +

Proceedings Article | 23 July 1993 Paper

Tunable ceramic phase shifters and their applications

Fathi Selmi, Raymond Hughes, Vijay Varadan, Vasundara Varadan

Proceedings Volume 1916, (1993) https://doi.org/10.1117/12.148472

KEYWORDS: Phase shifts, Waveguides, Dielectrics, Ceramics, Ferroelectric materials, Electrodes, Microwave radiation, Antennas, Ku band, PIN photodiodes

Read Abstract +

Proceedings Article | 23 July 1993 Paper

Fiber acoustic sensor

Aiguo Yin, Xiao-Qi Bao, Vijay Varadan, Vasundara Varadan

Proceedings Volume 1916, (1993) https://doi.org/10.1117/12.148484

KEYWORDS: Acoustics, Epoxies, Fiber optics sensors, Sensors, Signal processing, Transducers, Cladding, Wave propagation, Optical fibers, Polymers

Read Abstract +

Proceedings Article | 23 July 1993 Paper

Smart sensor systems for underwater acoustic applications

Vijay Varadan, Vasundara Varadan, Zhen Wu

Proceedings Volume 1916, (1993) https://doi.org/10.1117/12.148471

KEYWORDS: Sensors, Acoustics, Smart sensors, Coating, Actuators, Ferroelectric polymers, Computing systems, Wave propagation, Control systems, Reflection

Read Abstract +

Proceedings Article | 23 July 1993 Paper

Modeling integrated sensor/actuator functions in realistic environments

Jae-Wan Kim, Vasundara Varadan, Vijay Varadan

Proceedings Volume 1916, (1993) https://doi.org/10.1117/12.148504

KEYWORDS: Sensors, Solids, Chemical elements, Finite element methods, Smart materials, Environmental sensing, Actuators, Ferroelectric materials, Integration, Transducers

Read Abstract +

Proceedings Article | 23 July 1993 Paper

Smart-skin antenna technology

Vijay Varadan, Vasundara Varadan

Proceedings Volume 1916, (1993) https://doi.org/10.1117/12.148473

KEYWORDS: Antennas, Skin, Polymers, Electromagnetism, Composites, Radar, Reflection, Radio propagation, Camera shutters, Dielectrics

Read Abstract +

Proceedings Article | 23 July 1993 Paper

Smart coating materials for frequency-selective surface

Yushieh Ma, Vijay Varadan, Vasundara Varadan

Proceedings Volume 1916, (1993) https://doi.org/10.1117/12.148489

KEYWORDS: Coating, Composites, Dielectrics, Multilayers, FSS based metamaterials, Reflection, Ceramics, Barium, Strontium, Microwave radiation

Read Abstract +

Proceedings Article | 11 November 1991 Paper

Experimental study of chiral composites

Ru-Yen Ro, Vasundara Varadan, Vijay Varadan

Proceedings Volume 1558, (1991) https://doi.org/10.1117/12.49633

KEYWORDS: Composites, Polarization, Wave propagation, Scattering, Antennas, Absorption, Electromagnetism, Fused quartz, Optical activity

Read Abstract +

Proceedings Article | 11 November 1991 Paper

Theoretical modeling of chiral composites

R. Apparao, Vasundara Varadan, Vijay Varadan

Proceedings Volume 1558, (1991) https://doi.org/10.1117/12.49608

KEYWORDS: Composites, Wave propagation, Scattering, Phase velocity, Signal attenuation, Optical spheres, Polarization, Dielectrics, Microwave radiation, Dielectric polarization

Read Abstract +

Proceedings Article | 11 November 1991 Paper

Effective refractive indices of three-phase optical coatings

Yushieh Ma, Vijay Varadan, Vasundara Varadan

Proceedings Volume 1558, (1991) https://doi.org/10.1117/12.49621

KEYWORDS: Refractive index, Coating, Multiple scattering, Particles, Wave propagation, Scattering, Optical coatings, Correlation function, Spherical lenses, Titanium dioxide

Read Abstract +

Proceedings Article | 11 November 1991 Paper

Frequency-selective devices using a composite multilayer design

Yushieh Ma, Vijay Varadan, Vasundara Varadan

Proceedings Volume 1558, (1991) https://doi.org/10.1117/12.49620

KEYWORDS: Dielectrics, Composites, Microwave radiation, Scattering, Multilayers, Optimization (mathematics), Barium, Strontium, Wave propagation, Computer aided design

Read Abstract +

Proceedings Article | 11 November 1991 Paper

Sparse random distribution of noninteracting small chiral spheres in a chiral host medium

Akhlesh Lakhtakia, Vijay Varadan, Vasundara Varadan

Proceedings Volume 1558, (1991) https://doi.org/10.1117/12.49610

KEYWORDS: Optical spheres, Composites, Calcium, Scattering, Electromagnetism, Polarizability, Wave propagation, Protactinium, Lead, Electromagnetic scattering

Read Abstract +

Proceedings Article | 11 November 1991 Paper

Normally incident plane waves on a chiral slab with linear property variations

Akhlesh Lakhtakia, Vijay Varadan, Vasundara Varadan

Proceedings Volume 1558, (1991) https://doi.org/10.1117/12.49618

KEYWORDS: Matrices, Wave propagation, Differential equations, Scattering, Chemical elements, Electronics engineering, Acoustics, Composites, Radio propagation, Mechanics

Read Abstract +

Proceedings Article | 11 November 1991 Paper

Chirality and its applications to engineered materials

Vasundara Varadan, Vijay Varadan

Proceedings Volume 1558, (1991) https://doi.org/10.1117/12.49624

KEYWORDS: Wave propagation, Polarization, Scattering, Absorption, Composites, Electromagnetism, Active optics, Polarizers, Maxwell's equations, Dichroic materials

Read Abstract +

Proceedings Article | 1 October 1991 Paper

Comparison of analog and digital strategies for automatic vibration control of lightweight space structures

Suk-Yoon Hong, Vasundara Varadan, Vijay Varadan

Proceedings Volume 1489, (1991) https://doi.org/10.1117/12.46589

KEYWORDS: Control systems, Sensors, Actuators, Analog electronics, Vibration control, Ferroelectric materials, Feedback control, Amplifiers, Structural sensing, Radon

Read Abstract +

Proceedings Article | 1 October 1991 Paper

Ceramic phase-shifters for electronically steerable antenna systems

Fathi Selmi, Deepak Ghodgaonkar, Raymond Hughes, Vasundara Varadan, Vijay Varadan

Proceedings Volume 1489, (1991) https://doi.org/10.1117/12.46591

KEYWORDS: Phase shifts, Dielectrics, Ceramics, Temperature metrology, Ferroelectric materials, Microwave radiation, Antennas, Capacitors, PIN photodiodes, Reliability

Read Abstract +

Proceedings Article | 1 October 1991 Paper

Low-frequency chiral coatings

Ru-Yen Ro, Vasundara Varadan, Vijay Varadan

Proceedings Volume 1489, (1991) https://doi.org/10.1117/12.46586

KEYWORDS: Electromagnetism, Dielectric polarization, Maxwell's equations, Structural sensing, Particles, Lawrencium, Statistical analysis, Microwave radiation, Magnetism, Polarizability

Read Abstract +

Proceedings Article | 1 July 1991 Paper

Multiple-scattering effects on pulse propagation through burning particles

Yushieh Ma, Vijay Varadan, Vasundara Varadan

Proceedings Volume 1487, (1991) https://doi.org/10.1117/12.46560

KEYWORDS: Particles, Multiple scattering, Combustion, Scattering, Wave propagation, Refractive index, Radiative transfer, Receivers, Atmospheric particles, Beam propagation method

Read Abstract +

Proceedings Article | 1 July 1991 Paper

Discrete piezoelectric sensors and actuators for active control of two-dimensional spacecraft components

Janice Bayer, Vasundara Varadan, Vijay Varadan

Proceedings Volume 1480, (1991) https://doi.org/10.1117/12.46497

KEYWORDS: Sensors, Actuators, Ferroelectric materials, Antennas, Control systems, Chemical elements, Space operations, Electric field sensors, Acoustics, Vibration control

Read Abstract +

Proceedings Article | 1 October 1990 Paper

Electromagnetic wave propagation in discrete random chiral composite media

R. Apparao, Vasundara Varadan, Vijay Varadan

Proceedings Volume 1307, (1990) https://doi.org/10.1117/12.21653

KEYWORDS: Composites, Wave propagation, Radio propagation, Electro optical sensors, Sensors, Electromagnetic radiation, Polarization, Electromagnetism, Scattering, Electro optics

Read Abstract +

Proceedings Article | 1 October 1990 Paper

Polymer-based composites for RFI/EMI/ applications

Neil Williams, Vijay Varadan, Vasundara Varadan

Proceedings Volume 1307, (1990) https://doi.org/10.1117/12.21663

KEYWORDS: Polymers, Composites, Antennas, Signal attenuation, Electromagnetism, Electro optical sensors, Sensors, Electromagnetic coupling, Carbon, Calibration

Read Abstract +

Proceedings Article | 1 October 1990 Paper

Energy flux in the vicinity of a small dielectric particle

Yushieh Ma, Vijay Varadan, Vasundara Varadan

Proceedings Volume 1307, (1990) https://doi.org/10.1117/12.21656

KEYWORDS: Particles, Sensors, Electro optical sensors, Polarization, Dielectrics, Magnetism, Spherical lenses, Electro optics, Switches, Optical coatings

Read Abstract +

Proceedings Article | 1 October 1990 Paper

5-100GHz free-space microwave characterization setup

Vasundara Varadan, Vijay Varadan, Deepak Ghodgaonkar

Proceedings Volume 1307, (1990) https://doi.org/10.1117/12.21657

KEYWORDS: Antennas, Microwave radiation, Dielectrics, Calibration, Sensors, Electro optical sensors, Electromagnetism, Ceramics, Waveguides, Free space

Read Abstract +

Proceedings Article | 1 October 1990 Paper

Chiral polymer coatings for microwave applications

Vijay Varadan, Vasundara Varadan

Proceedings Volume 1307, (1990) https://doi.org/10.1117/12.21658

KEYWORDS: Polymers, Epoxies, Composites, Dielectrics, Microwave radiation, Electro optical sensors, Sensors, Optical coatings, Carbon, Absorption

Read Abstract +

Proceedings Article | 1 October 1990 Paper

Composite smart skins for airborne structures

Vasundara Varadan, Yongrae Roh, Xiao-Qi Bao, Thomas Howarth, Vijay Varadan

Proceedings Volume 1307, (1990) https://doi.org/10.1117/12.21672

KEYWORDS: Sensors, Composites, Skin, Electro optical sensors, Actuators, Control systems, Acoustics, Wave propagation, Ferroelectric polymers, Polymers

Read Abstract +

Proceedings Article | 1 October 1990 Paper

Modified flux model and its optical applications

Yushieh Ma, Vasundara Varadan, Vijay Varadan

Proceedings Volume 1307, (1990) https://doi.org/10.1117/12.21654

KEYWORDS: Scattering, Refractive index, Multiple scattering, Particles, Electro optical modeling, Reflectivity, Composites, Coating, Diffuse reflectance spectroscopy, Transmittance

Read Abstract +

Showing 5 of 292 publications

Proceedings Volume Editor (45)

SPIE Conference Volume | 29 June 2018

Nano-, Bio-, Info-Tech Sensors, and 3D Systems II

SPIE Conference Volume | 29 June 2017

Nanosensors, Biosensors, Info-Tech Sensors and 3D Systems 2017

SPIE Conference Volume | 8 September 2016

Nanosensors, Biosensors, and Info-Tech Sensors and Systems 2016

SPIE Conference Volume | 5 May 2015

Nanosensors, Biosensors, and Info-Tech Sensors and Systems 2015

SPIE Conference Volume | 23 April 2014

Nanosensors, Biosensors, and Info-Tech Sensors and Systems 2014

Showing 5 of 45 publications

Conference Committee Involvement (68)

Soft Mechatronics and Wearable Systems II

17 March 2025 | Vancouver, Canada

Soft Mechatronics and Wearable Systems

25 March 2024 | Long Beach, California, United States

Nano-, Bio-, Info-Tech Sensors, and Wearable Systems 2023

13 March 2023 | Long Beach, California, United States

Nano-, Bio-, Info-Tech Sensors, and Wearable Systems

7 March 2022 | Long Beach, California, United States

Nano-, Bio-, Info-Tech Sensors and Wearable Systems

22 March 2021 | Online Only, California, United States

Nano-, Bio-, Info-Tech Sensors and 3D Systems

27 April 2020 | Online Only, California, United States

Nano-, Bio-, Info-Tech Sensors and 3D Systems

4 March 2019 | Denver, Colorado, United States

Nano-, Bio-, Info-Tech Sensors and 3D Systems

5 March 2018 | Denver, Colorado, United States

Nano-, Bio-, Info-Tech Sensors and 3D Systems

26 March 2017 | Portland, Oregon, United States

Nano-, Bio-, Info-Tech Sensors and Systems

21 March 2016 | Las Vegas, Nevada, United States

Nano-, Bio-, Info-Tech Sensors and Systems

9 March 2015 | San Diego, California, United States

Nano-, Bio-, Info-Tech Sensors and Systems

10 March 2014 | San Diego, California, United States

Nano-, Bio-, Info-Tech Sensors and Systems

10 March 2013 | San Diego, California, United States

Nanosystems in Engineering and Medicine

10 September 2012 | Incheon, Korea, Republic of

SPIE Nanosystems in Engineering + Medicine

10 September 2012 | Incheon, Korea, Republic of

Nano-, Bio-, Info-Tech Sensors and Systems

12 March 2012 | San Diego, California, United States

Nano-, Bio-, Info-Tech Sensors and Systems

7 March 2011 | San Diego, California, United States

Nano-, Bio-, Info-Tech Sensors and Systems

8 March 2010 | San Diego, California, United States

Second International Conference on Smart Materials and Nanotechnology in Engineering

8 July 2009 | Weihai, China

Nano-, Bio-, and Info-Tech Sensors and Systems

9 March 2009 | San Diego, California, United States

Smart Structures, Devices, and Systems IV

10 December 2008 | Melbourne, Australia

Nanosensors and Microsensors for Bio-Systems

11 March 2008 | San Diego, California, United States

Microelectronics: Design, Technology, and Packaging III

5 December 2007 | Canberra, ACT, Australia

SPIE Microelectronics, MEMS, and Nanotechnology

4 December 2007 | Canberra, Australia

Nano-, Micro- and Bio-Sensors and Systems

21 March 2007 | San Diego, California, United States

Smart Structures, Devices, and Systems III

11 December 2006 | Adelaide, Australia

SPIE Smart Materials, Nano- and Micro-Smart Systems

10 December 2006 | Adelaide, Australia

Smart Electronics, MEMS, BioMEMS, and Nanotechnology

27 February 2006 | San Diego, California, United States

Microelectronics: Design, Technology, and Packaging II

12 December 2005 | Brisbane, Australia

Microelectronics, MEMS, and Nanotechnology

11 December 2005 | Brisbane, Australia

Smart Electronics, MEMS, BioMEMS, and Nanotechnology

7 March 2005 | San Diego, California, United States

Smart Structures, Devices, and Systems II

13 December 2004 | Sydney, Australia

Smart Materials, Nano-, and Micro-Smart Systems

12 December 2004 | Sydney, Australia

Smart Electronics, MEMS, BioMEMS, and Nanotechnology

15 March 2004 | San Diego, CA, United States

Device and Process Technologies for Microelectronics, MEMS, and Photonics

10 December 2003 | Perth, Australia

Microelectronics, MEMS, and Nanotechnology

10 December 2003 | Perth, Australia

Smart Sensors, Actuators, and MEMS

19 May 2003 | Maspalomas, Gran Canaria, Canary Islands, Spain

Smart Electronics, MEMS, BioMEMS, and Nanotechnology

3 March 2003 | San Diego, California, United States

MOEMS and Miniaturized Systems III

27 January 2003 | San Jose, CA, United States

Smart Structures, Devices, and Systems

16 December 2002 | Melbourne, Australia

SPIE's International Symposium on Smart Materials, Nano-, and Micro- Smart Systems

16 December 2002 | Melbourne, Australia

Smart Electronics, MEMS, and Nanotechnology

18 March 2002 | San Diego, California, United States

Electronics and Structures for MEMS II

17 December 2001 | Adelaide, Australia

International Symposium on Microelectronics and MEMS

17 December 2001 | Adelaide, Australia

Advanced Photonics Sensors and Applications II

28 November 2001 | Singapore, Singapore

Smart Structures and Materials 2001: Smart Electronics and MEMS

5 March 2001 | Newport Beach, CA, United States

Smart Electronics and MEMS

13 December 2000 | Melbourne, Australia

Smart Materials and MEMS

13 December 2000 | Melbourne, Australia

Smart Electronics and MEMS

6 March 2000 | Newport Beach, CA, United States

Bogus Conference--Organizing/Advisory Committee

29 November 1999 | Singapore, Singapore

Asia Pacific Symposium on Microelectronics and MEMS

27 October 1999 | Gold Coast, Australia

Smart Structures and Materials 1999: Smart Electronics and MEMS

1 March 1999 | Newport Beach, CA, United States

Smart Electronics and MEMS

2 March 1998 | San Diego, CA, United States

Smart Electronics and MEMS

11 December 1997 | Adelaide, Australia

Smart Materials, Structures, and Integrated Systems

10 December 1997 | Adelaide, Australia

Far East and Pacific Rim Symposium on Smart Materials, Structures, and MEMS

10 December 1997 | Adelaide, Australia

Smart Electronics and MEMS

5 March 1997 | San Diego, CA, United States

Smart Materials, Structures, and MEMS

11 December 1996 | Bangalore, India

Smart Materials, Structures and MEMS

11 December 1996 | Bangalore, India

Smart Structures and Materials 1996: Smart Electronics and MEMS

28 February 1996 | San Diego, CA, United States

Smart Electronics

2 March 1995 | San Diego, CA, United States

Smart Structures and Materials '95

26 February 1995 | San Diego, United States

Smart Structures and Materials 1994: Smart Materials

14 February 1994 | Orlando, FL, United States

Smart Structures and Materials 1993: Smart Materials

2 February 1993 | Albuquerque, NM, United States

Wave Propagation and Scattering in Varied Media II

22 July 1991 | San Diego, CA, United States

Structures Sensing and Control

2 April 1991 | Orlando, FL, United States

Electro-Optical maertials for Switches, Coatings, Sensor Optics, and Detectors

16 April 1990 | Orlando, FL, United States

Wave Propagation and Scattering in Varied Media

4 April 1988 | Orlando, FL, United States

Showing 5 of 68 Conference Committees

Course Instructor

SC243: RF MEMS and Reconfigurable Antennas for Wireless Communications

This course introduces the fundamentals of reconfigurable antennas and associated smart electronics including RF MEMS based switches, capacitors and filters. A newly developed Penn State fractal antenna architecture suitable for miniaturization of the system is discussed. Topics covered include: smart skin conformal antenna, electronically steerable antenna, multiband and wide band fractal antenna. This is followed by a critical survey of the currently available MEMS processing technologies related to antenna and RF circuits. Finally, the integration of the sensors, MEMS, and smart electronics into antenna architecture to conceive reconfigurable antenna for wireless communications is discussed.

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