声表面波滤波器的离散Green函数分析法

日本学者Hashimoto提出栅格有效介电常数和离散Green函数,并结合有限元方法分析了短路金属栅阵中声表面波的传输特性。由此开发了相应的Fortran应用程序。国际上许多从事声表面波器件的研发公司都使用该程序设计他们的产品。以Rayleigh波在128°YX-LiNbO3基片、铝金属栅中传播为例,给出根据Hashimoto程序运算的结果,读取禁带下边缘和禁带上边缘所对应的相对频率的数值,代入COM理论色散关系的数学表达式中,该表达式的图形就是由COM理论色散关系而确定的波数色散曲线,以提取耦合模参数。

A study of surface acoustic wave devices with discrete Green function

A Japanese scholar,Hashimoto,proposed using the effective permittivity of grating and the discrete Green function to investigate the properties of surface acoustic wave propagation in periodic metal gratings with the finite element method,and developed a program compiled by Fortran,which has been used to design the surface acoustic wave devices by many international companies.This paper gives the results of Hashimoto program with an example of Rayleigh waves propagation in aluminium grating on 128°YX-LiNbO3 substrate.The frequencies of the upper and lower stopband edges are read out and taken into the expression of the dispersion relation of COM theory.The figure drawn by this expression is the wavenumber dispersion curve to obtain COM parameters.