Reseach And Preparation Of X Band Substrate Integrated Waveguide Circulator

The communication industry has brought great convenience for work and life of people in the modern,and we have entered the era of 4G. 5G has been put on the development agenda.The transceiver, isolation, witches and other operations of the circulator plays very important role in a communication system. The design methods, theories, tools are moving forward. Also, the performance of circulators has been improving. At present, the development of microwave circulators has been toward to miniaturization, broadband, high reliability, especially in the microwave communication, energy technology, defense and aerospace fields.Because of the defect that the size and cost of the waveguide and that radiation and power of the microstrip line, people have been developed the SIW(substrate integrate waveguide)technology. The SIW technology has the advantages of waveguide and microstrip devices, which mean lower radiation and less insertion loss, higher Q value, and higher power capacity, smaller size. The passive devices and active devices could be integrated on the same substrate with the technology of PCB or LTCC, so we could reduce the connections and switches made by different processes to get good integration system which is suitable for mass production and application.In order to develop a high performance X band SIW circulator which are practical to application, those research and practice which have been done in this thesis are as the following areas:(1)Firstly we obtained Y type SIW circulator based on theory research and simulation experiment, and the electrical performance of the circulator are: VSWR is less than 1.2, and insertion loss is less than 0.4dB, return loss and isolation are more than 20 dB.(2)We turned the Y type circulator to T type circulator through the research of SIW match technology, and the T type circulator has a superior performance and is easier to be integrated.(3) Then we successfully designed cylindrical ferrite X-band circulator to achieve the same technical indicators, which have testified the validity of our method to design a SIW circulator. The return loss and isolation are more than 20 dB,and insertion loss is less than 0.5dB in the X band.(4) We have done a tolerance analysis for the triangle ferrite circulator, and analysis the influences of the performance of the circulator which are made by the various of the parameters of the device. This work has significant guiding significance for the device design or production(5) By the research for the principle of stripline test fixture and assembly process of device, the X-band SIW circulator has been prepared and tested. Sample volume is 12mm×12mm×0.635 mm.return loss is greater than 10 dB, and isolation loss is greater than 5dB in the entire X band. In the vicinity of 10 GHz center, return loss of less than 20 dB, insertion loss of less than 1dB, isolation of greater than 5 dB are obtained. This thesis established a relatively complete SIW circulator design system, which has a wide range of applications in the fields of microwave components, integrated circuits...