Development of a biologically inspired MEMS microphone

Zhang, Y. and Bauer, R. and Whitmer, W.M. and Brimijoin, W.O. and Uttamchandani, D. and Windmill, J. F. C. and Jackson, J.C. (2017) Development of a biologically inspired MEMS microphone. In: IEEE SENSORS 2017, 2017-10-29 - 2017-11-01, Scottish Exhibition and Conference Centre. (https://doi.org/10.1109/ICSENS.2017.8234383)

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Abstract

A multi-band operational MEMS microphone inspired by the hearing organ of Ormia ochracea is presented. The novel feature is that the device has both integrated capacitive and piezoelectric sensing capability. Similar to our previous designs, the new design works as a bi-directional microphone and has four separate resonance frequencies below 10 kHz, with intended application for human speech recognition scenarios. Since the capacitive sensing only depends on the displacement of the rotating plates, it provides 0.42 V/Pa acoustic sensitivity at the first, rocking resonance mode, while the electric response produced by the piezoelectric actuators is almost zero around the same frequency. However, the piezoelectric readout supports a faster transient response and produces less noise at low frequencies than the capacitive sensing method. The complementary interaction between these two sensing methods in one device thus increases the overall electrical response and its accuracy.