Some Properties of Saw in Piezoelectric Structures with Inhomogeneous Coating

A problem on surface sh-waves' propagation in a piezoelectric structure with a coating from a functionally graded material is considered. As a "base" material, a piezoelectric of 6mm class hexagonal syngony is used. The problem solution is based on the approach, which combines analytical methods of constructing the solution for homogeneous components and numerical methods of constructing the solution for inhomogeneous components of a heterogeneous structure. For problems with an electrically open or closed free surface, the transformation of the surface wave field, depending on the character of the change of the coating properties, is studied. Peculiarities of the surface waves' behaviour at different combinations of the coating and substructure materials are investigated. It is demonstrated, that by means of a special change of the coating properties it is possible to obtain the structure, on the surface of which Love waves or Bleustein-Gulyaev waves (BGW) are propagated, or the structure in which surface waves are absent in a definite frequency range.