Using a mutual acoustic impedance model to improve the time domain response of PMUT arrays

This paper presents an equivalent circuit model of a piezoelectric micromachined ultrasonic transducer (PMUT) array, combining an acoustic coupling model originally developed for capacitive micromachined ultrasonic transducer (CMUT) arrays and an electro-mechanical model of the individual PMUTs in the array. This model is experimentally validated with PMUT arrays of varied sizes and accurately predicts both the time response and frequency-domain bandwidth. The model also demonstrates that the transmit pulse response of PMUT arrays is strongly affected by acoustic coupling within the array.