SAW DIFFRACTION USING THE THIN-ELEMENT DECOMPOSITION METHOD

We adapt the angular spectrum of plane waves (ASPW) decomposition to n umerical simulations of the diffraction of surface-acoustic waves (SAW s) on an anisotropic model substrate, such as YZ lithium niobate. We u tilize the thin-element decomposition (TED) method, appropriately modi fied for an anisotropic substrate; we also introduce a novel ''average -wavenumber'' variation of this scheme; these are numerically found to be mutually consistent. We apply the TED method to simulate wave prop agation both in infinite periodic structures of metallized gratings an d also in finite gratings. We demonstrate that the ASPW provides a con venient and numerically fast tool for precise diffraction calculations in practical SAW devices which also display structural variations in the lateral direction, perpendicular to the principal direction of wav e propagation. Additionally, we compare the present TED method to wave guide theory in an analysis of the role of SAW reflections from the el ectrodes.