Novel Analysis Method of Driving-Point Admittance and Electro-Acoustic Conversion Efficiency of Interdigital Transducers by Six-Port Equivalent Circuit Model

In this paper, a simple six-port equivalent circuit model for interdigital transducers (IDT) [1] is applied to analyze the performance of IDT for SAW devices. As a result of our study, using the novel electrical equivalent circuit model combining with transmission line theory, we have derived new analysis formulae of input impedance and electro-acoustic conversion to enhance investigating of characteristics of SAW interdigital transducers. The features of the present analysis formulae are: (1) they are close to the actual performance due to including metallization effect, effective enough area ranging from fundamental frequency to harmonic frequency and the various secondary effects, (2) they can be programmed and computed easily. In addition, we also demonstrated the application of this approach by investigating the acoustical excitation of IDT for acousto-optical interaction.