Damped Aero-Acoustic Microphone With Improved High-Frequency Characteristics

With the mechanical resonance damped using a perforated back-plate underneath the sensing diaphragm, a piezoresistive aero-acoustic microphone with improved high-frequency characteristics is demonstrated. The sensing diaphragm and the damper back-plate were monolithically integrated in one process flow. The microphone was calibrated using a high-voltage electrical spark-discharge acoustic N-wave source. A sensitivity of ~0.33 μV/V/Pa, a bandwidth of ~520 kHz at 3-dB attenuation, and a significant damping of the mechanical resonance were realized.