Design And Fabrication Of Broadband Low-loss SAW Filter

SAW filter has the advantages of small size,low cost,simple process,strong antiinterference ability,etc.It has a very wide range of application requirements in the fields of mobile communication,radar,electronic countermeasures,satellite navigation,etc.With the development of mobile communication technology,higher operating frequency bands and faster data transmission have urgent needs for broadband low-loss SAW filters.Aiming at the broad application prospects and practical application requirements of broadband low-loss SAW filters,this paper studies the design and fabrication of broadband lowloss SAW filters.The main contents include:(1)The characteristics and laws of excitation and propagation of surface acoustic waves are studied,and the principle of wave modes of different surface acoustic waves and the motion characteristics of particles on the surface of elastic body are given.The influencing factors of the SAW propagation characteristics are analyzed,and the basic principles and characteristics of the interdigital transducer as well as the influence rules of the structural parameters are studied.(2)The LCR equivalent circuit model of the single-ended resonator is studied,and then the design method of the SAW ladder filter is introduced.The real propagation characteristics of surface acoustic waves on lithium niobate single crystal were simulated by COMSOL finite element analysis software,and its electrical characteristics were simulated by ADS software.Ladder SAW filter.(3)The fabrication process of SAW filter is studied.Based on L-Edit and MATLAB,bright-field and dark-field masks were designed,two sets of process flow of lift-off method and etching method were compared,and filter samples were produced.Finally,the quality control method is given for the filter samples and the performance parameters of the filter samples are tested.The test results basically meet the design goals,which effectively verifies the rationality and feasibility of the structural design,simulation analysis and technological process of this subject.