Ku-band Duplexer Research

With the advent of the 21 st century Internet age,communication technology has been developing rapidly,and the update of communication technology also makes people stricter about the requirements of communications devices.Microwave devices play an important role in communication devices,which are widely used in satellite communication,radar and electronic communication equipment.Especially the duplexer integrated with transmitting and receiving information in communication devices,its ability to receive and transmit signals is critical to the entire communication system.Therefore,the research on the miniaturization of the Microwave devices,the flexibility of interference signal suppression and device processing has never stopped.Especially with the rapid development of modern communication,the frequency resource space of each communication system has also become more and more crowded,so it is a meaningful work to design a filter which is small,deep band rejection,easy to process and tun.In this paper,the specific qualification of the duplexer have been definite combining with the actual needs of engineering.After studying the theory of microwave technology and researching on various kinds of cavity bandpass filters at home and abroad in depth,this paper uses the capacitance loading ridge resonator as a basic unit,designs a duplexer whose passband is respectively 12.75 GHz~13.25 GHz and 14.5 GHz~15.3 GHz by changing structure of cavity coupling and takes a comparative study using the measured data and the simulated data.The main work of this paper is as follows:Firstly,by referring to the existing literature about filters,it gives a brief overview of the development history and current situation of the filter and duplexer.Secondly,this paper introduces the theoretical knowledge of the band-pass filter and the T joint in detail,analyzes the advantages and disadvantages of various resonators and takes a research on the characteristics of single cavity.Thirdly,we build the model simulation by μWave based on the work above and analyze the feasibility of the model structure,then set the initial value of the model.Fourthly,according to the initial value obtained by μWave,the simulation model is established in the CST,and an E-plane waveguide diplexer which the center frequencies is respectively 13 GHz and 14.9 GHz is obtained.Compared with the traditional filter puts the metal columns and the coupling metal windows in the center of the cavity,in this paper,all the coupling metal windows and metal columns are on the same side,this improvement makes the device processing more convenient.After processing the material object,we compare the measuring results with the simulated results.Finally,summarizing the harvest and disadvantage of the work.