Microwave And Millimeter-wave Multi-way Power Combining Circuit And Key Technology Research

Power-combining techniques are widely used in microwave and millimeter wave systems,such as antenna feeder systems and solid-state power combining networks.Microwave and millimeter wave systems have various design requirements for the performance specifications of power dividers in different application settings.Specifically,simple structure,low cost and easy integration with other circuits are very important in the design of power divider to develop of miniaturized and integrated systems.This dissertation presents a series of circuit theories and designs of rectangular waveguide power dividers,radial waveguide power dividers,and substrate integrated waveguide(SIW)power dividers together with a comprehensive investigation into their theoretical analysis,design simulation,and experimental verification.Main contents are as follows:(1)An in-depth investigation into the working principle of the magnetic probe is conducted.A low-profile rectangular waveguide-coaxial line transition based on the embedded magnetic closed loop structure is presented and studied,and a waveguide power divider with low-profile waveguide-planar transition is proposed with the transition’s characteristics of simple structure,miniaturization and low processing cost together with the proposed transition and Wilkinson power divider mode.The working principle of two types of dual-magnetic-probe mode are studied and utilized.In accordance with electromagnetic theory of the center symmetrical dual-magnetic-probe structure,an out-of-phase power divider with rectangular waveguide-planar transition and a magic-T with low-profile waveguide-planar transition using rectangular waveguide as difference port are proposed.Based on the symmetrical dual-magnetic-probe mode and microstrip-slot line transition structure,a magic-T with low-profile waveguide-planar transition using waveguide as sum port is proposed.The above mentioned circuits are fabricated with standard printed circuit boards(PCBs).With its simple structure and low cost,the design provides a solution for system miniaturization and integration.(2)Several microwave multi-way power dividers are designed and analyzed.These include a broadband high-isolation multi-way radial power divider.By the comparison of the relationship between two kinds of path,a high isolation between output ports is achieved,which is the path between ports in the radial cavity and the path between ports through the isolation network.Another design is a wideband low-profile radial power divider using constant impedance transition.To make a low-profile radial cavity,the combining port-radial cavity transition is separated from the radial cavity-power splitting transition in addition to the utilization of constant impedance transform transmission line technology.Moreover,an amplitude-phase balancing technology is developed to improve layer-to-layer transition and applied in a low-profile power divider with uneven layout of output ports and the characteristics of low insertion loss and high amplitude-phase consistency.The last design in the category is an over-mode coaxial waveguide radial power divider for high power settings after studying the power capacity of power dividers,in which a matching load using high loss dielectric substrate is developed to reduce the cost of testing multi-way power divider with rectangular waveguide ports.(3)Two types of SIW power dividers for millimeter wave/sub-terahertz are designed and analyzed.Based on the equivalent circuit model,the transmission characteristics of stacked circuits with multilayer SIW are analyzed in order to create a transition from waveguide to multilayer stacked-SIW acting as a sub-terahertz high isolation multi-way stacked-SIW power divider.In another study,the evolution process from SIW to corrugated substrate integrated waveguide(CSIW)is investigated for the theory of large frequency ratio circuits,in combination with the utilization of spoof surface plasmon polaritons(SSPPs),leading to a novel composite mode transmission line(CMTL).A novel large-frequency ratio millimeter-wave dual-band power divider based on CMTL is presented,which combines the CMTL and half-mode CMTL with the Wilkinson power divider model to achieve a dual-band,large-frequency ratio with high isolation of output port.