Numerical simulation of leaky wedge acoustic wave excitation in piezoelectric structures

The excitation of pseudowedge waves in piezoelectric wedges using interdigital transducers on their surface has been investigated. The frequency dependence of propagating waves in a wedge made of lithium niobate on the orientation of the crystal under various boundary conditions has been calculated. This allowed for an evaluation of the effect of wedge face metallization on the propagation characteristics of both wedge and surface acoustic waves within it. Two-dimensional and three-dimensional finite element models were developed to study the conditions for the existence of leaky wedge waves and the possibility of their excitation. The ranges of crystal orientations where pseudowedge waves are observed were determined. Two widely used cuts of lithium niobate were considered: Z-cut and Y-cut. The effect of non-reciprocal wave propagation in lithium niobate was demonstrated for two adjacent rectangular wedges with faces formed by equivalent crystallographic planes.