Nonlinearity Modulating of the Scaln-Based Piezoelectric Micromachined Ultrasonic Transducer with DC Bias and Single-Tone AC Driving Signal

This paper presents a novel approach to modulating the nonlinearity of the ScAlN-based Piezoelectric Micromachined Ultrasonic Transducer (PMUT) by employing DC bias and single-tone AC signal. When the bias voltage is varied from -60 V to 60 V, the -3 dB effective bandwidth of (0,1) mode increases by 738% compared to the non-biased counterpart, which significantly expands the tuning excitation range of the harmonics. The displacement magnitude can also be tuned by applying DC bias, leading to a 21.2 dB enhancement in the 2<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">nd</sup> harmonic intensity. The adjustable effective frequency range and displacement amplitude afforded by the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\pm 60\ \mathrm{V}$</tex> DC bias facilitate a wide tuning range of harmonic numbers, spanning from 254 to 395.