Large band MEMS microphone for high frequency acoustic applications in air (10 kHz -1MHz)

In this paper, we present a test bench for the acoustic characterization of high frequency large band microphones (300 kHz – 1 MHz). An interferometry optical method is used for the calibration of the N-waves and the extraction of the pressure sensed by the microphones. Moreover, we compare the experimental results obtained from two different MEMS architectures. It is shown, that the optimization of the damping leads to better results reducing parasitic oscillations on the microphone response. The sensitivity achieved with the optimized device a flat low-frequency part of its frequency characteristics is 0.66 μV/V/Pa.