Zhang Zhongjie, Zeng Liang, Xu Chunlei, Rocha Rodrigo Tumolin, Xu Tingzhong
School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi Province 710049, China; Piezoelectric Microsystem Technologies (PMT), Microsystems, Silicon Austria Labs, Villach 9500, Austria.
School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi Province 710049, China.
Ultrasonics. 2025 Nov;155:107711. doi: 10.1016/j.ultras.2025.107711. Epub 2025 May 28.
This paper presents an analytical approach to determine optimal offset signals for driving air-coupled piezoelectric micromachined ultrasonic transducers (PMUTs), aimed at effectively reducing ring-down time and broadening bandwidth without compromising transmission sensitivity. To achieve this, a time-domain equivalent circuit simulation platform for PMUTs is developed to quickly obtain and analyze the air-coupled PMUTs response. This platform facilitates to fast obtain the ring-down times for different excitation signals and allows continuous adjustment of parameters for the offset signal waveform. The optimal offset signal waveform is then identified by comparing ring-down times generated across various parameter configurations of offset signals in simulation. The effectiveness of these optimized offset signals achieved through the proposed method is confirmed experimentally with different driving signals. For example, for a PMUT cell with a radius of 360 μm, the ring-down time is decreased by at least 85.49 % with the obtained optimal offset signal for short-period driving signals, while the -6dB bandwidth of the PMUT is increased by more than 3.85 times with the obtained optimal offset signal for long-period driving signals. By suppressing ring-down, the proposed method minimizes the blind zone, sharpens the echo envelope, and enhances positioning accuracy for ultrasound applications. Furthermore, the developed simulation platform has significantly improved the efficiency of time-domain simulations for PMUTs research, providing a solid foundation for future system-level optimizations and studies on PMUTs applications.
本文提出了一种分析方法，用于确定驱动空气耦合压电微机电超声换能器（PMUT）的最佳偏置信号，旨在有效减少余振时间并拓宽带宽，同时不降低传输灵敏度。为此，开发了一个用于PMUT的时域等效电路仿真平台，以快速获取和分析空气耦合PMUT的响应。该平台有助于快速获得不同激励信号的余振时间，并允许连续调整偏置信号波形的参数。然后，通过比较仿真中不同偏置信号参数配置下产生的余振时间，确定最佳偏置信号波形。通过所提出的方法获得的这些优化偏置信号的有效性，在实验中用不同的驱动信号得到了证实。例如，对于半径为360μm的PMUT单元，对于短周期驱动信号，使用获得的最佳偏置信号时，余振时间至少减少了85.49%，而对于长周期驱动信号，使用获得的最佳偏置信号时，PMUT的-6dB带宽增加了3.85倍以上。通过抑制余振，所提出的方法最小化了盲区，锐化了回波包络，并提高了超声应用的定位精度。此外，所开发的仿真平台显著提高了PMUT研究时域仿真的效率，为未来PMUT应用的系统级优化和研究奠定了坚实的基础。
