Although silicon is the most used material in micro-electro-mechanical-systems, due to the excellent mechanical properties, it has poor performance for generating audible sound by capacitive micro-speakers. This paper studies the capability of dielectric elastomer material instead for generating the directional sound in the human hearing regime. Dielectric elastomers are a branch of smart materials with high desired and practical specifications such as large deformation, energy-efficient, lightweight, biocompatible, and fast response which share the common characteristics of changing their shape under an applied electrical voltage or charge. An elastic circular dielectric elastomer micro-plate with compliant electrodes on both sides suspended over the unmoving plate as a capacitive micro-structure has been modeled as a diaphragm of the micro-speaker. Then the Bessel panel array has been considered in a square matrix form composed of the number of dielectric elastomer micro-speakers. The nonlinear equation of the vibrations of a micro-speaker’s diaphragm under an electrostatic loading and equations of the sound pressure and sound radiation pattern have been presented and solved. The results have shown that utilizing dielectric elastomer-based micro-speakers in a Bessel panel array can generate a directional audible sound pressure in the human hearing range. In addition, the results clear that the desired sound waves in the human audible range and a private or personal listening zone can be produced through adopting an optimal value among the excitation frequencies, diaphragm numbers, radii and inter-element spaces of a Bessel panel array.

中文翻译：

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用于产生定向可听声音的基于 DE 的电容式微型扬声器

尽管硅是微机电系统中使用最多的材料，但由于其优异的机械性能，它在电容式微型扬声器产生可听声音方面的性能较差。本文研究了介电弹性体材料在人类听觉范围内产生定向声音的能力。介电弹性体是智能材料的一个分支，具有高变形、节能、轻质、生物相容性和快速响应等特性，它们具有在施加电压或电荷下改变其形状的共同特征。一个弹性圆形介电弹性体微板，两侧带有柔性电极，作为电容微结构悬挂在不动的板上，已被建模为微型扬声器的膜片。然后将贝塞尔面板阵列考虑为由多个介电弹性体微型扬声器组成的方阵形式。提出并求解了静电载荷作用下微型扬声器振膜振动的非线性方程、声压方程和声辐射模式方程。结果表明，在贝塞尔面板阵列中使用基于介电弹性体的微型扬声器可以产生人类听觉范围内的定向可听声压。此外，