This article presents a piezoelectric micromachined ultrasonic transducer (pMUT) modified with a piston diaphragm term as piston diaphragm pMUT (PD-pMUT). The transmission sound pressure level (SPL) and the frequency bandwidth of the modified transducer can be remarkably improved by adding a piston diaphragm on the central circular diaphragm. In this work, a lumped model, an acoustic resonance model, and an equivalent circuit model are established to study the multiresonance mechanism. The second resonance peak is contributed by the interference acoustic wave generated between the circular and piston diaphragms. This work demonstrated a simulated far-field average SPL up to 132.2 dB in the single modified piston diaphragm structure and a 28.1%-6-dB frequency bandwidth by theoretical analysis and parameter optimization. The bandwidth is 3.31 times of the traditional pMUT with aluminum nitride (AlN) in air. In addition, the PD-pMUT has a -6-dB frequency bandwidth of up to 66%, which is 1.4 times of traditional pMUT in the liquid-coupled operation. The proposed PD-pMUT provides a new approach for the application of high transmission power and broad bandwidth transducers.

中文翻译：

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一种基于活塞模式的新型耦合压电微机械超声换能器。

本文介绍了一种压电微机械超声换能器 (pMUT)，其使用活塞隔膜项进行了修改，称为活塞隔膜 pMUT (PD-pMUT)。通过在中央圆形振膜上增加活塞振膜，可以显着提高改进后的换能器的传输声压级（SPL）和频带宽。在这项工作中，建立了集总模型、声学共振模型和等效电路模型来研究多共振机制。第二共振峰由圆形和活塞膜片之间产生的干涉声波贡献。这项工作通过理论分析和参数优化证明了在单个改进的活塞膜片结构中模拟的远场平均 SPL 高达 132.2 dB，以及 28.1%-6-dB 的频率带宽。带宽为 3。空气中氮化铝 (AlN) 的传统 pMUT 的 31 倍。此外，PD-pMUT 具有高达 66% 的 -6dB 频宽，是传统 pMUT 液耦合操作的 1.4 倍。所提出的 PD-pMUT 为高传输功率和宽带宽传感器的应用提供了一种新方法。