压电晶体-固体-液体结构中IDT的体声波激励

对压电晶体－固体（层）－液体结构中叉指换能器的体声波激励效应进行了深入探讨，通过引入压电晶体－固体层界面的界面有效介电常数，研究了叉指换能器的体声波激励效应与晶体切向、电边界条件及固体层归一化厚度之间的关系。数值分析表明，电边界条件对叉指换能器体声波激励效应的影响可忽略；体声波激励效应与压电晶体切向和固体层归一化厚度密切相关；通过选择恰当的晶体切向、固体层归一化厚度和慢度，叉指换能器仅向液体中激励体声波，且可确定出最强体声波激励时的结构参数。文中所得结果，为有关液体声传感器结构的优化设计奠定了基础。

Excitation of Bulk Acoustic Waves by Interdigital Transduceras in the Structure of Piezoelectric Crystal-Solid Layer-Liquid

The excitation of bulk acoustic waves(BAWs) by interdigital transducers(IDTs)is thoroughly studied in the structure consisting of piezoelectric crystal solid layer liquid.The effective permittivity at the interface of piezoelectric crystal solid layer is employed to analyze the BAW excitation effect.The relationship of BAW excitation efficiency versus both orientation of crystal and normalized thickness of solid layer( kd ) is discussed.The numerical simulations show that the influence of electrical boundary condition on BAW excitation by IDTs may be neglectable,and that the BAW excitation is greatly concerned with the orientation of crystal and kd .It also shows that there is the most effective BAW excitation only into the interior of liquid if the appropriate crystal orientation, kd and slowness are given.The analysis results in this article lay a foundation for optimizing design of liquid sensor structure.