A new simulation method for nonlinear characteristics of SAW devices

In recent years, the linearity performance of the RF front end part of mobile phone handsets is a one of very hot topics. In such a situation, the requirement of high linearity to SAW duplexers has become strong. In this paper, a novel simulation method for nonlinear signals has been proposed. The nonlinear stress and current are represented by introducing nonlinear terms into the piezoelectric fundamental equations. They are connected as voltage and current sources in the electrical equivalent circuit of a SAW device, and the nonlinear signals observed at arbitrary external terminals are estimated. Very good agreement between the simulation and the measured values has been obtained for the third-order harmonic and IMD of SAW resonators.