A nonlinear elastic model for predicting triple beat in SAW duplexers

This paper proposes simple and precise nonlinear simulation techniques for surface acoustic wave (SAW) duplexers, especially for the in-band 3rd order nonlinear distortion, the so-called ‘triple beat’. The simulation model is based on the nonlinearity of SAW stress vs. strain (nonlinear elasticity of SAW), and needs just one nonlinear parameter, which represents the 3rd order nonlinear coefficient for the elastic constant. The simulation results of the triple beat for 1.9 GHz Personal Communications Service (PCS) SAW duplexers demonstrate fairly good agreement with the measurements with an accuracy of less than 1 dB.