A new generalized modeling of SAW transducers and gratings

A general coupling-of-modes analysis of SAW transducers and gratings is presented. The analysis is applicable to the complete continuum of SAW devices, from transducers with or without internal reflections to grating reflectors comprised of grooves or metallic stripes. The analysis incorporates several important phenomena not previously included in analyses of this type. Both the effects of finite-electrode resistivity and spatially varying propagation loss are accounted for. In addition, the analysis is sufficiently general to permit the modeling of complex devices on relatively arbitrary crystal orientations. Three coupled first-order differential equations are obtained relating the forward and reverse propagating acoustic-wave amplitudes i the device and the current on the busbars. These equations lead directly to simple expressions for some very fundamental characteristics of SAW devices