Research On Miniaturized Microwave Multi-port Coupled Power Divider Circuit

As the basic passive component of a microwave system,couplers and power dividers are widely used in the design of mixers,array antenna feed networks,and amplifiers,and restrict the performance of the entire system.In order to adapt to the development trend of high integration of microwave circuits in recent years,while ensuring performance,the coupler and power divider need to be miniaturized.The circuit system design tends to be dense and compact,and there is an urgent need for multi-port balanced circuit with high stability and good anti-interference ability.In addition,the development of modern communication systems is accompanied by an increase in the operating frequency of the system,and the use of new transmission structures such as gap waveguides to improve the performance of passive circuits in the millimeter wave band has also become a research hotspot.In order to solve the problems mentioned above,this thesis is focused on the research of compact microwave multi-port coupling/power division circuits,and the main contribution of this work is summarized as bellow:1.Analysis and design of compact dual-band branch-line coupler with short/open-ended stubs: Traditional branch line couplers can realize power division between the straight output port and the coupling output port,and ensure good port match and isolation.On this basis,by loading half-wavelength open/short-ended stubs,dual-frequency operation is achieved while keeping the size of the coupler compact.The passband frequency and power division ratio of the two proposed structures can be adjusted conveniently,and the structure is simple and easy to process.2.Analysis and design of a miniaturized eight-port balanced dual-frequency coupler based on a double-sided parallel strip line(DSPSL): The basic characteristics of DSPSL and the mixed-mode S-parameters are introduced.Using the eight-port mixed-mode S-parameters and the structural characteristics of DSPSL,an eight-port balanced coupler with common-mode rejection over broadband is designed.In addition,by loading a pair of half-wavelength short-ended stubs,the dual-frequency operation of the balanced coupler is realized.The passband frequency ratio and power division ratio can be easily adjusted by changing the transmission line impedance value.3.Analysis and design of Ka-band broadband Gysel power divider based on the ridge gap waveguide(RGWG): The groove-pin unit cell is designed to widen the GWG bandwidth.Based on the proposed GWG unit structure,a Ka-band Gysel power divider is designed.And designed a new Ka band RGWG to microstrip line conversion structure.The proposed structure has a wide bandwidth,low loss,compact size,simple structure and easy processing.