Design And Fabrication Of P-Band Narrow-Band Low-Loss SAW Filter

Surface Acoustic Wave(SAW)filters have the advantages of small size,high reliability,low cost,and good stability,and are widely used in mobile communications,satellite navigation,radar detection,and other fields.They are one of the key components in RF systems.SAW filters have significant advantages over traditional crystal filters and are gradually replacing traditional filters as the mainstream products in the market.This dissertation focuses on the application prospects and practical application requirements of narrowband and low-loss SAW filters in the P-band.It conducts related research on the design and production of SAW filter samples,which has significant research value and practical significance.The main contents of this dissertation include:(1)The basic theory and propagation mechanism of SAWs were studied.The wave modes and proton motion characteristics of different types of SAWs were given.The factors affecting the propagation characteristics of SAWs were analyzed,and the working principle of the metal finger transducer and SAW filter were studied.The main parameters,classification,and characteristics of the filters were provided.(2)The equivalent circuit model of the trapezoidal SAW filter structure was studied.Through relevant research on the structure of the resonator,the propagation characteristics and structural optimization of the designed SAW filter were analyzed using finite element simulation software COMSOL and electrical simulation software ADS.A narrowband and lowloss SAW filter in the P-band that meets the target requirements was designed.(3)The preparation process of the SAW filter was studied.The preparation process flow of the filter was designed,and a dark field mask plate was designed based on Tanner Tools and Matlab.Using lithium tantalate wafers and peeling process,a narrowband and low-loss SAW filter sample in the P-band was successfully prepared.(4)Based on the prepared SAW filter sample,the quality of the chip process was controlled using confocal microscopy,the morphology of the completed metal finger transducer was inspected,and the performance parameters of the packaged SAW filter were tested using a network analyzer.The test results basically met the design targets,effectively verifying the rationality and feasibility of the parameter design,simulation analysis,and process flow of this project.