Design And Technique Research Of Band V SAW Duplexer For WCDMA Mobile Phone

With the rapid development of wireless communication technology and mobile internet,mobile phone is indispensable consumer goods in people's daily life.Its global shipments are rapid growth.Due to the inheritance of history and technology development,mobile phone needs to work at multiple communication modes and in a variety of frequencies.Such as GSM and CDMA800 in 2G,WCDMA,TDSCDMA and CDMA2000 in 3G,TDD-LTE and FDD-LTE in 4GThe working frequency band is from 700MHz to 3500MHz.These communication modes can be divided into two types as frequency division duplex(FDD)and time division duplex(TDD).The FDD mode is widely used all over the world.In the current market,SAW duplexer is supplied almost all by foreign manufacturers.Such as TDK-EPCOS,AVAGO,MURATA,TAIYO,WISOL etc.,these companies almost monopolized the design,batch of production and marketing of SAW duplexers.And the pricing power is also controlled by them.For a production and consumption super-country of mobile phone like China,it's unable to bear the pain.This paper,based on above background,selects the Band V SAW duplexer,the most commonly used in WCDMA system,as the research object.Content of this dissertation covers fundamental theories,design mode,chip technology,flip-chip and injection molding technology,test method of SAW duplexer and test result.Tx channel chip was designed using ladder structure.Rx channel was designed using LCDMS structure.SAW duplexer chip was made with multiple lithography,coating film,lift-off process.The process flow of reballing,dicing,flip-chip,sticking film,injection molding,and cutting was designed to manufacture samples of Band V SAW duplexer.And the suitable technological parameters were found by many experiments.According to microwave measurement method,test jig was designed and test system was set up.And the characteristics of SAW duplexer were tested.The test results of the samples showed that the typical value of insertion loss in Tx channel 824MHz to 849MHz was 1.4dB,the amplitude ripple was about 0.4dB.And the typical value of insertion loss in Rx channel 869MHz to 894MHz was 1.7dB,the amplitude ripple was about 0.4dB.The isolation from Tx to Rx in Tx channel was greater than 57dB,and 49dB in Rx channel.The input power,+29dBm CW,can be meet at +50? temperature for Tx channel.It can meet the actual use of customer application.