Elastic waves excited into a thick anisotropic plate by interdigital transducers

Waves emanating from an interdigital transducer deposited on a general anisotropic half-space are analyzed. Using the Fourier integral approach, the wave field is computed at larger distances from the source within the saddle point approximation. Singularities of the integrant correspond to the various excited waves: the well-known Rayleigh wave (or the pseudo-Rayleigh wave), surface skimming bulk waves, and deep radiated acoustic waves. The approach fails when any dispersion curve exhibits an inflexion point, and in this case the wave field is shown to be trapped between caustics. Radiation diagrams are given for quartz and LiNbO₃ configurations. Experiments have been performed on 1-mm and 6-mm plates. Singly rotated quartz cuts with transducers parallel and normal to the X axis have been measured. In addition to the previously mentioned waves, transmission curves reveal a more complex structure with linear and nonlinear plate modes. Observation of piezoelectric solitons in surface-skimming bulk wave (SSBW) plates is reported