Hybrid Finite‐Element Analysis of Surface Acoustic Waveguides with One‐Wavelength Period along Propagation Direction

Abstract

SUMMARYThe finite-element analysis method based on the hybrid variational principle is proposed for analysis of the dispersion characteristic of periodic surface acoustic waveguides with a one-wavelength period. A new formulation is used for finite element approximation applied to the periodic function part of Floquet modes. This approach allows elimination of the uniform field without sinusoidal variations in the periodic direction, which has been included in the conventional hybrid finite-element analysis to directly approximate the entire field distribution. Hence, an analysis of periodic waveguide structures with a one-wavelength period is now possible. Specifically, the reflection properties are studied for a metallic grating reflector with a one-wavelength period formed on an X-112°Y LiTaO 3 substrate and for a DART and an EWC-SPUDT.