Effects of DC Bias Tuning on Air-Coupled PZT Piezoelectric Micromachined Ultrasonic Transducers

In this paper, we report an air-coupled piezoelectric ultrasonic micromachined transducer (PMUT) using a lead-zirconate-titanate (PZT) piezoelectric layer. A dc bias voltage applied to the PZT film controls its polarization and intrinsic stress, tuning the frequencies of two closely-spaced resonance modes of the rectangular shaped PMUT. At an optimal bias voltage of approximately 5 V, the modes ne...