Hybrid acoustic waves in piezoelectric plates

The conditions of zero-order and high-order hybridization of the acoustic waves propagating in a piezoelectric crystal plate have been studied. The dependence of the phase velocity of the hybrid waves on the parameter hf (h = plate thickness, f = wave frequency) is established for the potassium niobate and lithium niobate plates possessing various crystallographic orientations and sheet conductances. It is found that hybridization takes place when the sheet conductance exceeds a certain value, which can vary within broad limits depending on the plate material and orientation. The degree of dispersive repulsion of the coupled modes increases with the electromechanical coupling coefficient.