Numerical Analysis of Parameters of Pseudosurface Acoustic Waves in Lithium Niobate and Tantalate Crystals

The results of the analysis and calculation of the propagation parameters of leaky surface acoustic waves in lithium niobate and tantalate crystals are presented. Test structures for analysis based on the finite-element method using the COMSOL Multiphysics package are described. A method is proposed to determine the key parameters needed for the design of devices based on surface acoustic waves. The phase velocity of the wave, the coefficient of electromechanical coupling, and the coefficient of reflection from a single electrode for industrially used piezoelectric substrates are calculated. The calculated key parameters can be used to design resonators and filters based on leaky surface acoustic waves. It is shown that the calculated data are in agreement with the literature data. The calculated results are compared with the experimental data using an example of a ladder filter.