A surface micromachined capacitive microphone for aeroacoustic applications

Abstract

This paper presents improved results for a micromachined dual-backplate condenser microphone designed for aeroacoustic applications. Previous microphone characterization yielded an unacceptably high noise floor. This paper presents improvements to the noise floor through the use of a low-noise voltage amplifier and improved packaging. With bias voltages of ±9.3 V, an average sensitivity of 166 μV/Pa and a noise floor of 22.7 dB/√Hz for a 1 Hz bin centered at 1 kHz are obtained. The noise floor is reduced to a level below that of other MEMS-based aeroacoustic microphones while maintaining sufficient bandwidth and maximum pressure.