EQUIVALENT NETWORKS FOR SAW INTERDIGITAL TRANSDUCERS

An equivalent network approach is described for the analysis of surface-acoustic-wave interdigital transducers. Circuit parameters can be theoretically determined by applying the finite-element method to an infinite array. In this approach, all the effects of piezoelectric perturbation, mechanical perturbation, and energy storage are taken into account. To show the validity and usefulness of this approach, examples are computed for both single- and double-electrode interdigital transducers and one-port resonators. For single- and double-electrode interdigital transducers on 128-degrees-Y XLiNbO3, X 112-degrees-Y LiTaO3, 45-degrees-X Z Li2B4O7, and ST(g) X quartz substrates, the dependence of excitation characteristics on electrode thickness and metallization ratio is investigated in detail. For a 128-degrees-Y-X LiNbO3 substrate, frequency responses of various one-port resonators are also investigated.