Performance of aluminum nitride-based piezoelectric micromachined ultrasonic transducers under different readout configurations

In this paper, a low noise amplification circuit is designed for aluminum nitride-based piezoelectric micromachined ultrasonic transducers (PMUTs) with three different sensing configurations. The acoustic pressure sensitivity and noise resolution of PMUTs corresponding to different readout configurations are analyzed and characterized. With the differential readout configuration, the acoustic pressure sensitivity of the PMUTs is improved by 5.76 dB (re: 1 V mu Pa-1) on average, and the noise resolution is reduced by about 8 dB at 500 Hz (re: 1 mu Pa (Hz(1/2))(-1)). Compared to the conventional readout configuration, both theoretical analysis and measurement results show that the output voltage of PMUTs is doubled with the differential readout configuration and thus the acoustic pressure sensitivity is improved. Moreover, the noise resolution of PMUTs is reduced and thus the signal-to-noise is improved. This work offers new insight on improving the receiving performance of PMUTs.