Modeling of internal reflections and diffraction in SAW transducers

Abstract

A method for the combined simulation of electrode reflections and diffraction in surface acoustic wave (SAW) filters is presented. The electrode reflections are modeled with a mixed nodal impedance/scattering paramenter (MNS) formalism which is based on a P-matrix analysis. Field-shorting and mass-loading reflections as well as end effects are taken into account. The results of this calculation are used to define frequency- and position-dependent excitation strengths for the sources within the transducer. These source strengths are used in an extended angular-spectrum-of-waves model. The improved accuracy of this approach is demonstrated for a broadband delay line and a bandpass filter.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>