Research Of Filter And Multiplexer Based On SISL

The rapid development of modern communication system requires more and more higher performance of the transceiver system.As the front-end device of RF transceiver,the performance of filter has a direct impact on the quality of the whole communication system.Therefore,the filter components with advantages of miniaturization,low insertion loss,high out-of-band suppression and easy integration have become the focus of researchers.In this paper,the designs adopt the substrate integrated suspended line(SISL)as the design platform.Compared with the filters of the traditional transmission lines,they have the advantages of double-sided circuit,low loss,high Q value,selfpackaging and easy integration.Because of that the single-frequency filter has been unable to meet the requirements of the current communication system,dual-band filter,multi-channel duplexer and multiplexer have gradually become the focus of research.As the name implies,a dualband filter is one structure that can make two different frequency bands work at the same time.Multiplexers,which allow multiple channels to share a single wideband antenna,greatly reduce the area of the RF system.The most common is the transceiver duplexer.This paper studies the design of high performance dual-band band pass filter,duplexer and triplexer.First,the research status of filters and multiplexers are briefly introduced,and the development trend and application value are discussed.The traditional transmission line and SISL are introduced and compared.Second,the concept and calculation method of the basic performance of the filter are introduced.Two analysis methods commonly used in filter design and analysis are also explained in detail.Third,SISL is selected as the design platform to design two dual-band band pass filters according to the design objective.The first design is the filter for WiFi application,in which the input-output feeder plays multiple roles of exciting the lower circuit,independently generating the pass band and introducing the transmission zero.The second design is a multi-mode broadband dual-band filter,and there are four modes in the second passband.Then,the basic theory,structure and design methods of the duplexer and multiplexer are introduced,which provides the theoretical basis for the following design.Finally,a multiplexer structure with good expandability was proposed based on SISL.Two duplexers of different frequency bands and the extended triplexer were designed based on this structure.The performance of the structure was verified by machining and testing the three designs.