Spurious bulk waves in SAW filters with apodized transducers

Abstract

The authors report the simulation of the bulk wave transmission characteristics of planar acoustic devices on arbitrary substrates. Starting from the basic acoustoelectric differential equations, the analysis is based on the Green's function formalism and the Ritz-Galerkin method. In contrast to previously published papers, the authors apply these methods to devices with large apodized IDTs (interdigital transducers) and treat the interaction with bulk waves rigorously during generations as well as reception. They derive a CPIM (charge potential interrelation matrix) formulation of the voltage weighting analysis method for apodized IDTs and compare it with the track-by-track analysis method. Finally, simulation results of the spurious bulk wave responses of a TV filter with 170 IDT fingers are presented.

Keywords

This publication has 8 references indexed in Scilit:

Accurate determination of material constants of piezoelectric crystal from SAW velocity measurements
Published by Institute of Electrical and Electronics Engineers (IEEE) ,2003
Analysis and measurement of transducer end radiation in SAW filters on strongly coupling substrates
IEEE Transactions on Microwave Theory and Techniques, 1989
Interdigital Transducer Interaction with SAWS and BAWS
Published by Institute of Electrical and Electronics Engineers (IEEE) ,1987
The evaluation of the input admittance of SAW interdigital transducers
Journal of Applied Physics, 1979
Analysis of Generation and Detection of Surface and Bulk Acoustic Waves by Interdigital Transducers
IEEE Transactions on Sonics and Ultrasonics, 1977
Plate Mode Coupling in Acoustic Surface Wave Devices
IEEE Transactions on Sonics and Ultrasonics, 1976
Field Analysis of Large Weighted Transducers
Published by Institute of Electrical and Electronics Engineers (IEEE) ,1976
Acoustic surface wave filters
Proceedings of the IEEE, 1971