Modeling And Simulation Of SAW Device

SAW filters compared with other filters have many of characteristics, such asanti-interference、small size、consistency、suitable for mass production and so on. Themare widely applied in communications、electronic warfare or television. SAW devices havereceived significant attention for they have many of outstanding properties and are widelyapplied.Accurate modeling is the key to design high-performance SAW devices. This paperfocuses on the study on modeling and simulation of SAW device, in order to provide the highaccuracy model for the production of SAW devices.This paper covers the basic theory of SAW, the basic simulation model of SAW,SAW resonator and its COM model, the frequency dispersion of （100）AlN/（111）Diamondlayered structure, FEM simulation of SAW devices and so on. The main work is as follows.Under deeply understanding of SAW’s COM model, we use the model to analyze theresonance response of the LiNbO₃SAW two-port resonator, and write the correspondingsimulatiuon code by Matlab. Through the frequency response curve of the resonator, we canoberve that the narrow peak at the resonance frequency.Because of （100）AlN/（111）Diamond layered structure with frequency dispersion, thethickness of （100）AlN film have great influence on SAW phase velocity. In order to designthe layered structure SAW device, we must be able to accurately predict the dispersion effectof the layered structures. We build christoffel equation of layered films by SAW’s christoffelequation and its boundary conditions. By solving the equation, we can get the frequencydispersion curve of the layered structure. In addition, we calculate the material constants of（100）AlN and （111）Diamond.By Comsol software, we simulate one-port resonator of the piezoelectric crystal,one-port resonator of the layered structure and two-port resonator of the layered structure.From the eigenfrequency analysis, we can observe the symmetric and anti-symmetric mode,propagation characteristics and the attenuation characteristics; By frequency response analysis,we can calculator the input admittance of YZ-LiNbO₃and （100）AlN/（111）Diamond SAWdevices. Input admittance analysis is helpful for us to design the impedence matching of thewireless SAW device.