Properties of interdigital transducers in relation to the substrate crystal symmetry

Exclusively from the crystal symmetry, we obtain results concerning properties of interdigital Rayleigh waves along high-symmetrical crystal directions. Three cases of high-symmetrical directions are considered. The crystal symmetry determines the properties of the piezoelectric tensor and consequently the wave excitation by transducers. These considerations enable one to ascertain the positions of the transduction centers and the influence of internal reflections on the amplitude characteristics. Furthermore, we are able to discuss the old question “crossed-field or in-line model?”