Rapid 2D FEM simulation of advanced SAW devices

Modern high-performance SAW filters utilize thin-film technology to optimize losses, temperate stability, filter bandwidth, and manufacturing sensitivity. Fast design of these complicated structures calls for accurate and more general simulation tools. The versatility of the finite element method (FEM) makes it attractive for this purpose. However, the application of FEM in the SAW field has been hampered by the associated very large memory requirements and excessive computation times. Here, we describe frequency-domain FEM simulation of SAW devices with the hierarchical cascading algorithm, including thermal effects. The method utilizes the periodic block structure, which is typical to SAW devices, to eliminate redundant calculations from FEM. The approach has all the advantages of FEM, with — for structures with high degree of periodicity — drastically reduced memory consumption and computation time.