Distribution of the dynamic strain and stress components within a layered film of a SAW resonator on LiTaO3

Based on recent reports about the acoustical power distribution in SAW resonators we present an analytical method to determine the distribution of the dynamic strain and stress components in SAW resonators on LiTaO₃. This enables us to calculate the absolute strain and stress values for each point in the layer of a resonator for any driving condition and frequency. The SAW resonator is described by a P-Matrix based model, which gives us the distribution of the potential power and the resulting energy density. For calculation of the relative strain and stress values we used the partial wave method. Using the correlation between the total acoustic power and the energy density distribution normal to the substrate surface, we can calculate the strain and stress values for a given input power. For the direct experimental verification of our calculations we measured the SAW induced displacements as a function of input power.