Silicon micromachined condenser microphone array for bionic ears

Abstract

A miniature condenser microphone array that combines array signal processing and MicroElectro-Mechanical Systems technologies is developed for bionic ears. Electroacoustical analogy is employed to establish a linear dynamic model of the silicon microphone, while a quasi-static analysis based on the $,ire difference method is conducted to$nd the collapse condition. The array configuration seryes two purposes: enhancement of the sensitivify and directivify of the transducer. A least square beamfonning design based on the template resulting from the Multiple Signals Classification algorithm is proposed to achieve a highly directive beam pattern. To minimize the parasitic effects on the MEMS device, a System-on-Chip design is proposed in the paper. The design is composed of a microphone module, a bias circuit, an impedance matching circuit, an on-chip amplifier and array beamfonning filter. The perjormance of the proposed design is evaluated in the frequency response through numerical simulations and the results are discussed