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This paper presents a broadband THz generation and detection technique based on high-speed bipolar transistors and PIN diodes that act as fast switches. Traditionally, fsec lasers and photo-conductive antennas are used to produce psec pulses in the time domain. These techniques require an expensive and bulky laser, optical alignment, and moving parts that add to the complexity of the system. To alleviate these issues, laser-free fully electronic THz sources and detectors are designed and fabricated. The source technology can produce THz signals up to 1.1THz with linewidth of 2Hz. The detector technology can capture THz signals up to 500GHz.
To produce and radiate THz pulses, a DC current is passed through an on-chip antenna that acts as an inductor in low frequencies and stores magnetic energy. The DC current is then disconnected with a bipolar transistor in a few psec. This event causes a large voltage transient on the antenna resulting in radiation of pulses with duration of less than 2psec. The produced THz pulse is then radiated with an on-chip antenna. With this method, THz pulses with repetition rate up to 15GHz are generated and radiated. To detect the THz pulses, a silicon-based detector is designed and fabricated. The detector captures THz pulses with an on-chip antenna. The received THz pulse is then sampled by a fast bipolar transistor. In addition to the transistor-based approaches, this presentation will also introduce silicon-based PIN diodes as alternative solutions for THz pulse generation and detection.
Using the source and detector technology developed in this work, several systems are implemented. These systems include a THz gas spectrometer, a hyper-spectral imaging system, a micro-doppler radar, and a wireless communication link. In this presentation, the design, implementation, and performance of these systems will be reported as well.
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