An Analysis of an Equivalent Circuit Model for an Interdigital Surface-Acoustic-Wave Transducer

Abstract

This paper presents a new and simplified equivalent circuit model for an IDT. The model developed here provides more accuracy than the well-known crossed field Smith-model, since it contains the energy storage effect in addition to usual secondary effects. By applying the image parameter theory to the new model, the admittance matrix Yij of the equivalent three-port model for an N-pair IDT has been derived in concise closed form. As an application, the relations of the radiation conductances to metallization ratios for an IDT are investigated.