Analysis of reflective SAW gratings for SH‐type modes using finite‐element method

Abstract

Abstract A solution based on the finite‐element method (FEM) is presented for the analysis of SH‐type surface acoustic wave gratings. Although the FEM has already been applied to the discontinuities in elastic waveguides for SH‐type modes, only the isotropic substrate has been treated. Also, it is difficult to apply the FEM directly to many discontinuities such as grating reflectors due to excessive computation time and computer memory requirements. This paper presents a numerical approach to the analysis of SH‐type surface acoustic wave gratings on anisotropic substrates. To apply the FEM directly to many discontinuities, the substructure method is introduced. As a result, mutual interaction between surface waves and bulk waves is automatically taken into account over the entire discontinuity region. To show the validity and usefulness of this approach, examples are computed for various gratings on PZT‐4, 41° Y‐X LiNbO 3 , and 36° Y‐X LiTaO 3 substrates.