Precise modeling of complex SAW structures using a perturbationmethod hybridized with a finite element analysis

摘要

Surface acoustic wave (SAW) devices used in high stabilitynoscillators or filters are generally designed to exhibit a lownsensitivity to thermal and mechanical perturbations. Theoreticalndevelopments based on variational equations have been proposed to modelnthese phenomena. Mechanical perturbations applied to simple geometriesnof the propagation substrate can be analytically considered using thisnapproach. However, because of the strong dependence of mechanicalneffects on the geometry of the substrate, analytical models cannotnprovide realistic predictions on complex SAW structures subject tonexternal stresses, vibrations, or accelerations. In this paper, annadaptation of the Tiersten-Sinha perturbation method is proposed, whichncombines the finite element analysis (for a precise prediction ofnquasi-static perturbations) and analytical variational equations of SAWnpropagation. Comparison of results obtained using simple analyticalnmodel and the proposed approach shows a very good agreement in the casenof symmetrical radial in-plane compression on circular plates andnmonoaxial bending moments applied on rectangular substrates. Thisnvalidation enables the consideration of more complicated configurationsnand allows using special stress-compensated SAW quartz cuts