Effects of air cavity on fly-ear inspired directional microphones: a numerical study

Haijun Liu; Miao Yu

doi:10.1117/12.880619

14 April 2011 Effects of air cavity on fly-ear inspired directional microphones: a numerical study

Haijun Liu, Miao Yu

Proceedings Volume 7981, Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems 2011; 79811V (2011) https://doi.org/10.1117/12.880619
Event: SPIE Smart Structures and Materials + Nondestructive Evaluation and Health Monitoring, 2011, San Diego, California, United States

Abstract

The superacute ear of the parasitoid fly Ormia ochracea has inspired the development of a variety of novel miniature directional microphones for sound source localization, in which the effects of air cavity backing the eardrums are often neglected without validation. In the original testing on the fly ear, the integrity of the air space is shown not to be the key to the intertympnal coupling. However, it does not necessarily mean that the tympanum can be treated as in vacuo, and the effects of the air cavity backing the eardrums have yet to be fully understood. In this article, a normalized version of our previous model of air-backed circular membranes is derived to study the conditions under which the air cavity can be indeed neglected. This model is then used to study a fly-ear inspired directional microphone design with two clamped circular membranes mechanically coupled by a bridge. The performance of the directional microphone with air cavity is evaluated in comparison to its counterpart in vacuo. This article not only provides more insights into the fly ear phenomena, but builds a theoretical foundation on whether and how to take the air cavity into account in the design of pressure sensors and directional microphones in general.

Citation Download Citation

Haijun Liu and Miao Yu "Effects of air cavity on fly-ear inspired directional microphones: a numerical study", Proc. SPIE 7981, Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems 2011, 79811V (14 April 2011); https://doi.org/10.1117/12.880619

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