A Flush-Mount, IEPE MEMS Piezoelectric Microphone for Aeroacoustic Applications – AIAA Aug 2021

This paper describes the development and experimental characterization of a flush-mount aeroacoustic microphone designed for through-wall installation. The aluminum nitride piezoelectric microelectromechanical systems (MEMS) sensor is fabricated using a novel, low-cost approach to creating backside electrical contacts, creating a hydraulically smooth surface without the use of through-silicon vias. Integrated electronic piezoelectric (IEPE) circuitry enables operation of the sensor using commercially available IEPE-enabled data acquisition systems. An improved assembly process yields variations of <10 μm across the microphone package surface. Characterization of the device demonstrates improved performance over previously developed piezoelectric aeroacoustic microphones, with a low-frequency cut-on of 52 Hz and a sensitivity of 186 μV/Pa, minimum detectable pressure (MDP) of 44.0 dBSPL, and experimentally verified dynamic range in excess of128 dB based on a maximum input pressure of172 dBSPL at 1 kHz.

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