Design And Research Of High Frequency Bulk Acoustic Wave Resonator

With the rapid development of mobile communication technology,the communication spectrum and the frequency are also increasing.These impose higher requirements on the RF front-end components in communication systems.Bulk acoustic wave（BAW）filters offer distinct advantages over traditional ceramic filters and surface acoustic wave filters in terms of their working frequency,Q value,and insertion loss.Furthermore,they have broad development space and application prospects in modern mobile communication systems.Therefore,this thesis will analyze and simulate the bulk acoustic wave resonator,and design a bulk acoustic wave filter based on it.The main research contents are as follows:Firstly,the basic structural parameters of the bulk acoustic wave resonator are designed.In order to obtain extremely large electromechanical coupling factor,the appropriate cut angle is selected by analyzing the electromechanical coupling factor of Li Nb O₃ with different cut angle.Through analyzing the influence of electrode shape,area,material,and thickness on the resonator performance,a square electrode shape is selected and a double-layer electrode structure is designed.Based on the basic structural design,two different transverse mode suppression structures are designed,and the suppression effects of the two structures are compared and analyzed.Then solidly mounted resonator（SMR）type substrate is applied to the basic design,and analyzed its influence to the device performance,including binding of energy and Q valueFinally,a coupled resonator filter is simulated and designed,and the feasibility of using LN as the piezoelectric layer material for the filter is verified,realizing high frequency,large bandwidth,and low insertion loss filtering performance.The filter performance is further optimized by designing the coupling layer structure and parallel coupling capacitor.The final results show that it can be applied to the N77 band in 5G systems.