On the existence of surface acoustic waves on piezoelectricsubstrates

摘要

The existence of surface waves on anisotropic materials was provennunder fairly general conditions by Lothe and Barnett in 1976. But, untilnnow, the status of surface waves on piezoelectric materials has remainednunresolved. This paper presents general existence theorems for surfacenwaves on piezoelectric substrates. It is demonstrated that for shortncircuit boundary conditions a surface wave solution must exist undernvirtually any circumstances. However, for a free surface, comparativelynstringent existence conditions are required. Numerical examples arengiven for both free and shorted surfaces, and it is demonstrated that,nin some situations, a surface wave solution may not exist for freensurface propagation. The existence proofs were developed as a result ofntheoretical work on Green function modeling, which is now the preferredntechnique for rigorous SAW and pseudo-SAW device analysis. Thenmechanisms of the existence proofs and the associated mathematicalnresults give great insight into the structure and properties of thenGreen functions and include many results that are directly relevant tondevice analysis