Hybrid method for the precise calculation of the general dyadic Greens functions for SAW and leaky wave substrates.

Branch, Darren W.

关键词: 97;    GREEN FUNCTION;    SOUND WAVES;    CALCULATION METHODS;    ALGORITHMS;    EIGENVALUES;    EIGENVECTORS;    PERMITTIVITY;    TRANSDUCERS Displacement gages.;    Wave mechanics.;    Acoustic surface waves.;    Green's functions.;   

DOI  :  10.2172/942184
RP-ID  :  SAND2008-2262
PID  :  OSTI ID: 942184
Others  :  TRN: US200902%%160

学科分类：社会科学、人文和艺术（综合）

美国|英语

来源: SciTech Connect

【 摘 要 】

Recently, the generalized method for calculation of the 16-element Green's function for analysis of surface acoustic waves has proven crucial to develop more sophisticated transducers. The generalized Green's function provides a precise relationship between the acoustic stresses and electric displacement on the three mechanical displacements and electric potential. This generalized method is able to account for mass loading effects which is absent in the effective permittivity approach. However, the calculation is numerically intensive and may lead to numerical instabilities when solving for both the eigenvalues and eigenvectors simultaneously. In this work, the general eigenvalue problem was modified to eliminate the numerical instabilities in the solving procedure. An algorithm is also presented to select the proper eigenvalues rapidly to facilitate analysis for all types of acoustic propagation. The 4 x 4 Green's functions and effective permittivities were calculated for materials supporting Rayleigh, leaky, and leaky longitudinal waves as demonstration of the method.