Micromachined Piezoelectric Acoustic Sensor with Enhanced SNR for Audio Applications

Abstract

A MEMS piezoelectric acoustic sensor (PAS) with enhanced signal-to-noise ratio (SNR) can be productive in audio applications. Notably, the simultaneous improvements on sensitivity and noise can amplify the SNR; whereas, the traditional works were enclosed either with sensitivity enhancement, or noise optimization. As a consequences, the traditional works had a lack of either high sensitivity, or low noise. In this paper, an analytical and experimental work on the SNR enhancement has been reported. At first, an analytical model was developed using the common influential factors of a PAS, and then, the model was numerically analyzed to achieve the optimized parameters. For the proof-of-concept, the optimized parameters were fabricated for the experimental verification. In experiment, the measured SNR was 67.03 dB which is the highest SNR so far for the circular-shaped PAS, and found 4.02% difference from the analytically achieved SNR. The modal frequency of the PAS was achieved at 10.18 kHz with the bandwidth of 2~10 kHz which can be extended for audio applications with higher SNR.