Propagation of surface acoustic waves in prestressed anisotropic layered piezoelectric structures

The propagation of surface acoustic waves in layered piezoelectric structures with initial stresses is investigated. The phase velocity equations are obtained for electrically free and shorted cases, respectively. Effects of the initial stresses on the phase velocity and the electromechanical coupling coefficient for the fundamental mode of the layered piezoelectric structures are discussed. Numerical results for the c-axis oriented film of LiNbO3 on a sapphire substrate are given. It is found that the fractional change in phase velocity is a linear function with the initial stresses, and the electromechanical coupling factor increases with an increase of the absolute values of the compressive initial stresses. The results are useful for the design of surface acoustic wave devices.