层状压电介质中一种奇特的电声波

A PECULIAR ACOUSTOELECTRIC WAVE INPIEZOELECTRIC LAYERED STRUCTURE

对于由不同压电材料作为基底及覆盖层(两者之间为理想连接）的层合结构，本文发现并证明当它们的压电常数满足确定的关系时，在这种结构中将会传播一种奇特的电声波．这种波传播时机械扰动和电磁扰动是相互耦合的，但机械扰动只发生在覆盖层中．也就是说，这种面波传播时质点的水平偏振运动只发生在覆盖层中，而基底中质点的位移始终为零．文中建立了上述面波存在的条件及相应的相速度方程，并给出了数值算例．

The propagation characteristic of the Rayleigh wave in the piezoelectric solids canbe applied to make many kinds of surface acoustic wave devices such as the filters, delay linesand amplifiers etc., these devices are utilized extensively in the fields of electronic, ultrasonictechnology and microwave communication. But there is a kind of lateral and horizontal polarizationsurface wave (acoustoelectric wave or Bleustein-Gulyaev wave) which can only propagates in the.piezoelectric medium. The characteristic of B-G wave is notutilized in general cases up to nowfor its large penetration depth.As to a layered structure with different piezoelectric layer and substrate in ideal contact, it isdiscovered and proved by analytical method in this paper that when their piezoelectric and dielec.trio constants are satisfied with certain relationship, a peculiar acoustoelectric wave (shear surfacewave) could propagate in the structure. As the wave propagates, its mechanical perturbationand electromagnetic perturbation are coupled, but its mechanical perturbation only takes place inthe layer and the displacement of the particles in the substrate is always zero. The propagationcondition of the above surface wave and its corresponding velocity equation are obtained, severalnumerical examples are also given. The results in this paper indicate that the thickness of thelayer can be the same order as the wavelength, and even shorter than a wavelength. Therefore,the work of this paper not only reveal a peculiar motion in the piezoelectric layered structure, butprovide the theoretical foundation for the practical utilization of acoustoelectric wave as well.