Gazzola C, Zega V, Corigliano A, Lotton P, Melon M
Civil and Environmental Engineering Department, Politecnico di Milano, Milan, 20133, Italy.
Laboratoire d'Acoustique de l'Université du Mans (LAUM), UMR 6613, Institut d'Acoustique - Graduate School (IA-GS), CNRS, Le Mans Université, Le Mans, 72085, France.
J Acoust Soc Am. 2024 Feb 1;155(2):1503-1514. doi: 10.1121/10.0024939.
Piezoelectric micro-electro-mechanical-system (MEMS) speakers are emerging as promising implementations of loudspeakers at the microscale, as they are able to meet the ever-increasing requirements for modern audio devices to become smaller, lighter, and integrable into digital systems. In this work, we propose a finite element model (FEM)-assisted lumped-parameters equivalent circuit for a fast and accurate modeling of these types of devices. The electro-mechanical parameters are derived from a pre-stressed FEM eigenfrequency analysis, to account for arbitrarily complex geometries and for the shift of the speaker resonance frequency due to an initial non-null pre-deflected configuration. The parameters of the acoustical circuit are instead computed through analytical formulas. The acoustic short-circuit between the speaker front and rear sides is taken into account through a proper air-gaps modeling. The very good matching in terms of radiated sound pressure level among the equivalent circuit predictions, FEM simulations, and experimental data proves the ability of the proposed method to accurately simulate the speaker performance. Moreover, due to its generality, it represents a versatile tool for designing piezoelectric MEMS speakers.
压电微机电系统（MEMS）扬声器正成为微尺度扬声器的一种有前途的实现方式，因为它们能够满足现代音频设备对更小、更轻以及可集成到数字系统中不断增长的要求。在这项工作中，我们提出了一种有限元模型（FEM）辅助的集总参数等效电路，用于对这类设备进行快速且准确的建模。机电参数是从预应力有限元本征频率分析中推导出来的，以考虑任意复杂的几何形状以及由于初始非零预偏转配置导致的扬声器共振频率的偏移。声学电路的参数则通过解析公式计算得出。通过适当的气隙建模来考虑扬声器前后侧之间的声学短路。等效电路预测、有限元模拟和实验数据在辐射声压级方面的良好匹配证明了所提出方法准确模拟扬声器性能的能力。此外，由于其通用性，它是设计压电MEMS扬声器的一种通用工具。
