Research On High Performance Surface Acoustic Wave Resonators

In order to meet the requirements of the development of 5G mobile communication technology,the design of mobile communication devices is gradually developing to higher frequency and better performance.As a basic part in mobile communication devices,the frequency and performance of acoustic resonator will have a significant impact on the devices.Among acoustic resonators,surface acoustic wave(SAW)resonators occupy a large market.From the past research,many different resonator structures are proposed.Among these structures,the Incredible High-Performance SAW(IHP SAW)is widely used for its excellent performance and high resonant frequency.Based on IHP SAW,this thesis focusses on the methods to improve the performance of the resonator and suppress the spurious of the resonator.First of all,based on the basic theory,this thesis studies the piezoelectric theory and resonance mode of SAW.The calculation of some basic design parameters of SAW are shown,and simulation methods used in this thesis for SAW are briefly introduced.Then,the different IDT and reflector structures of IHP SAW are proposed.Firstly,Dummy electrode,Piston mode structure and Double busbar structure are used in the IDT structure to suppress the transverse mode of the resonator and provide energy confinement.The effect of these structures on improving the performance of IDT is verified by simulation.Then,due to the similar electrode structure between the reflector and IDT,the structures in IDT may be also useful in the reflector.To verify this,the proposed method of periodic 3D simulation of reflector is used to simulate different reflector structures.It is concluded that the structures used to improve performance in IDT,such as Piston mode and Double busbar,are also useful in reflector.On the basis of the previous simulation,the resonators with different reflectors are processed,and the MBVD model is used to analyze the test results.The problems and shortcomings of the processing results are discussed.Finally,although the processing of resonators with different structure reflectors does not meet the expectations,it can still be seen that some structures used to improve performance in IDTs are also useful in reflectors.In the process of designing IDT structures for resonators,the same structure can be used in reflectors for performance improvement.