The Design Of Low Insertion Loss And Wide Passband 3.7GHz Saw Filter For 4G-LTE TDD Base Station

With the development of 4G-LTE communication technology,surface acoustic wave(SAW)filter plays an important role in the RF front-end.The increasing communication frequency and faster data transmission require SAWF to develop the center of the higher frequency,wider bandwidth and more excellent band rejection.This paper focuses on the implementation of high frequency and low loss filter in YX-41oLiNb03.By the trapezoidal structure design of the series and parallel resonator connections,we can get low loss SAW filter with the center frequency of 3.7GHz.The feasibility of the design model is verified by simulation;Secondly,a series of simulations are carried out for the capacitance ratio and series of series and parallel resonators,then the insertin loss and the suppression meet the requirement;Finally,the window function of the resonator is weighted and the layout program is given.This paper introduces the basic theory of SAW,realization of low loss filters and related SAWF products,details of the COM parameters and the COM equation.The filter frequency response is obtained by using COM equation to simulate the SAWF P matrix.The path to realize high frequency SAW filter was studied by stripping process which realizes the development of 3.7GHz SAW filter.Through the performance test,high and low temperature test,ESD test and power test of 3.7GHz SAW filter after packaging,we can confirm the design model is correct.