BACKWARD TRANSFER ACOUSTIC-WAVES IN CUBIC-CRYSTAL PLATES

The propagation of transverse acoustic waves in the direction [110] an d in the plane (<(1)over bar 10>) of cubic piezoelectric crystals is t heoretically analyzed. Dispersion equations were derived by solving th e system of equations of elasticity theory and electrodynamics subject to standard boundary conditions at free surfaces. It is demonstrated that plates of piezoelectric cubic crystals can carry transverse backw ard waves (with opposite phase and group velocities) and waves with co mplex wave numbers. The effect of conducting layers occurring on plate surfaces is analyzed.