Thin plate model for transverse mode analysis of surface acoustic wave devices

This paper proposes a physical model for the analysis of transverse modes in surface acoustic wave (SAW) devices. It is mostly equivalent to the scalar potential (SP) theory, but so flexible to include various effects such as anisotropy, coupling between multiple modes, etc. First, the theory of the two-dimensional wave equation for a shear-vertical bulk wave on an infinitesimally thin piezoelectric plate is investigated. Most of all parameters needed in the model can be derived from those for the 1D coupling-of-mode (COM) model due to their equivalence. To show the effectiveness, the model is applied to the analysis of Al/128°YX-LiNbO₃ substrate structure, and the simulation results are in good agreement with analytical result.