The system-on-chip design of a silicon micromachined condenser microphone array

Abstract

A miniature condenser microphone array that combines array signal processing and micro-electro-mechanical systems (MEMS) technologies is presented. A linear dynamic model and a quasistatic analysis are presented. The array configuration serves two purposes: enhancement of the signal-to-noise ratio (SNR) and the directivity of sensor. A least-squares beamforming design based on the template resulting from the Multiple Signals Classification algorithm is proposed to achieve a directive beam pattern. To minimize the parasitic effects on the MEMS device, a system-on-chip design composed of a microphone module, a dc bias circuit, an impedance matching circuit, and array beamforming filters is proposed in the paper. The performance of the proposed design is evaluated in terms of the frequency response, SNR improvement, and directional response through numerical simulations and experiments. (C) 2004 Acoustical Society of America.