Influence of liquid on properties of backward acoustic waves in piezoelectric plates

In the paper the characteristics of shear-horizontal direct and backward acoustic waves of the higher orders propagating in XY potassium niobate plates in band including the cutoff frequencies have been theoretically investigated. It also has been theoretically investigated the influence of nonviscous and nonconductive liquid on their properties. It has been found that the presence of liquid are reduced the velocity of waves under study. The range of the backward wave existence is increased with increasing of the wave order number.