Sensitivity of interface acoustic waves to the nature of the interface

A finite element analysis/boundary integral method (FEA/BIM) model is used to investigate the influence of the geometry and the composition of the interface on the properties of interface acoustic waves (IAW). The method considers a finite region treated by FEA and submitted to periodic boundary conditions, taking into account radiation in both the bottom and the top half-spaces. The influence of the IDT thickness and of the material choice for the interfacial film are discussed for some cuts and structures. It is found that the most significant contribution of the interface geometry is to the ability of an IAW device of efficiently guiding waves, i.e. to the propagation losses.