Bleustein-Gulyaev waves in a transversely isotropic piezoelectric layered structure with an imperfectly bonded interface

Bleustein-Gulyaev (BG) waves in a transversely isotropic piezoelectric substrate-layer structure with an imperfectly bonded interface are investigated, and the dispersion equations with respect to the phase velocity are obtained for both electrically open and shorted conditions. The phase velocity achieves a value that is small relative to the BG wave velocity of the piezoelectric layer when the interface is imperfect. Meanwhile, the imperfect interface has a strong influence on the electromechanical coupling factor. The effect of the imperfect interface on the particular BG wave, which can only propagate in the layer, is investigated, with the aim of reducing the penetration depth of BG waves. The outcome is widely applicable, and it can be utilized in the design of surface acoustic wave devices with high performance.