A MEMS-based piezoelectric microphone was developed for aeroacoustic measurements and consists of a circular composite annular ring of PZT for electromechanical transduction. An electroacoustic equivalent circuit model was used to design the device. Experimental characterization yielded a sensitivity of 1.66 my V/Pa, with a linear dynamic range from (35.7-169 dB, re 20 my Pa). The resonant frequency was estimated to be 59.0 kHz by measuring the actuator frequency response. This is the first reported piezoelectric microphone developed specifically for aeroacoustic applications. Based on the experimental results reported earlier, this microphone meets and exceeds the general specifications required for 1/4 scale wind tunnel testing and certification. Furthermore, the self-powered nature of the transduction facilitates the construction of microphone arrays for airframe noise source localization, by eliminating the need to distribute power throughout the array. Future work includes the extension of the composite plate model to large deflections. These models will then be validated against the current design and then subsequently used to synthesize an optimal design. A new package design is necessary to provide a vent channel to the microphone for a controlled low frequency roll-off. Further characterization of the microphone is needed in order to determine variability from device to device, and to investigate reliability issues such as fatigue and stability of the piezoelectric modulus.
Development of a micromachined piezoelectric microphone for aeroacoustics applications
Entwicklung eines mikrogefertigten piezoelektrischen Mikrophons für aeroakustische Messungen
Journal of the Acoustical Society of America ; 122 , 6 ; 3428-3436
2007
9 Seiten, 15 Bilder, 1 Tabelle, 39 Quellen
Article (Journal)
English
A MEMS microphone for aeroacoustics measurements
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