Bioinspired low noise circular-shaped MEMS directional microphone

Abstract

The traditional state-of-the-art miniature directional microphones suffer from a higher noise level mainly due to size constraints. Herein, a miniature directional microphone mimicking the fly Ormia ochracea’s ear anatomy is presented with the prime focus on achieving higher signal-to-noise ratio at reduced size. The microphone has circular shape with aluminum nitride (AlN)-based piezoelectric readout scheme deposited at the center of the diaphragm. The 3-3 transduction mode is adopted for sensitivity enhancement. The microphone testing is performed in an anechoic chamber. Besides the bidirectional response, the A-weighted noise under broadband excitation is ∼29  dBA, which is lower than the optical directional microphone of Miles et al., which is the most prominent noise analysis work in the area of fly inspired MEMS directional microphone.