R. Lowell Smith
Texas Res. Inst., 9063 Bee Caves Rd., Austin, TX 78733
Applications of both linear and nonlinear theories of piezoelectricity to transduction problems commonly ignore internal material dissipation effects. Such losses can be represented phenomenologically via the introduction of complex dielectric, elastic, and piezoelectric coefficients. However, there is some confusion in the literature with respect to the proper partitioning of electrical and mechanical attributes in the presence of piezoelectric coupling. This paper is a review of this situation wherein dissipation coefficients are motivated from more fundamental physical insights. Equivalent circuit models are useful both for developing this perspective and summarizing the results. Suggestions are also presented for generalizing the celebrated Mason model to include the coupling of orthogonal modes via Poisson dilation. This formalism is intended to provide straightforward procedures for computing piezoelectric oscillator performance characteristics using a personal computer. The approach is evaluated via regression analysis in terms of its self-consistency for interpreting Tonpilz oscillator admittance data. The procedures developed are expected to be applicable for the interpretation of data associated with a variety of other electroacoustic structures.