Research On Multi-frequency Power Division Filter Based On Microstrip Transmission Line

As two types of passive components that are crucial in wireless communication systems,power dividers and filters have received extensive attention from domestic and foreign scholars.Therefore,the integrated design of the two types of components has become a research hotspot in this direction.In addition,with the comprehensive coverage of 4G networks and the gradual operation of 5G networks,single-frequency communication systems can no longer meet today's multi-standard communication needs,and the demand for multi-frequency communication is increasing.Therefore,it is of great significance to study the design of multi-frequency filtering power dividers.However,in the case of meeting the multi-band communication standards,there is still a lack of relevant research on how to reduce the size of the filtering power dividers and get good port isolation as well as frequency selectivity.In view of this,this thesis starts from the voltage distribution characteristics of the transmission line,and realizes the design of a dual-frequency filtering power divider,two triple-frequency filtering power dividers,and a quad-frequency filtering power divider by loading isolation resistors between the resonators.The main content of the thesis is summarized as follows:1.Design a dual-frequency filtering power divider and a triple-frequency filtering power divider based on a quarter-wavelength transmission line.Firstly,the two-wire coupling and three-wire coupling are theoretically analyzed,and then the voltage and electric field distribution characteristics of the quarter-wavelength terminal short-circuit line are analyzed.Then,the voltage and electric field distribution characteristics of the terminal short-circuit transmission line and the stub-loaded resonator are combined to give a double design of a dual-frequency filtering power divider and a triple-frequency filtering power divider.The filter response analysis is provided as well.Finally,the two filtering power dividers are simulated,processed and tested to verify the effectiveness of the two circuit designs.2.A high-performance triple-frequency filtering power divider is designed based on the three-quarter wavelength transmission line.Firstly,analyze the voltage and electric field distribution characteristics of the three-quarter wavelength terminal short-circuit transmission line.And then take the open-circuit stub loaded resonator and the short-circuit stub loaded resonator as examples.The controllable frequency characteristics of two resonators are carefully analyzed.Then,from the perspective of open-circuit stubs loaded with resonators and three-quarter wavelength terminal shortcircuit transmission lines,the design of a multi-frequency filtering power divider with independent control of the passband center frequency and bandwidth is imagined.In addition,analyze the adopted E-type resonator with the even-odd mode analysis method,give the odd-mode and even-mode resonant frequencies,and design a highperformance triple-frequency filtering power divider based on the topology model of the multi-frequency filtering power divider.Finally,circuit processing and testing are performed to verify the validity of the proposed theory.3.Design a quad-frequency filtering power divider with good performance based on a half-wavelength transmission line.Firstly,the analysis of the voltage and electric field distribution of the half-wavelength terminal open-circuit transmission line is given,and then the loaded multi-mode resonator is deeply studied.After that,quadfrequency filtering power divider is realized by combining the half-wavelength terminal open-circuit transmission line and the multi-mode resonator.Finally,the effectiveness of the design method is verified by simulation and testing.