Study Of Higher Order Mode Microwave Components Based On Substrste Integrated Waveguide

With the requirements on the performance of the modern wireless communication continue to improve,highly integrated microwave and millimeter-wave system integration technology is also evolving.The performance of the guided-wave structure plays a key role in the design of the millimeter wave system and its components.As a new type of transmission line similar to waveguide structure,substrate integrated waveguide not only enjoys the advantages of traditional rectangular waveguide,such as high power handling capability,low radiation loss,but also has the advantages of the flat transmission line,that is easy to integrate and manufacture.In recent years,SIW has been widely applied to a variety of microwave components.Due to measurement purposes and component integration requirements,the research on transitions between SIW and other transmission lines is an important topic for SIW components.Until now,many transitions from other transitions,such as microstrip lines to SIW,coupled microstrip lines to SIW,CPW to SIW,have been researched theoretically and practically.All the transitions above are designed for the dominant mode(TE₁₀ mode),but little research has been done on the wideband direct transitions to the higher mode SIW.With the increasing application of SIW to millimeter system,the higher mode SIW components have attracted more and more interests.The application of higher mode SIW components enjoys two advantages: simplifying the structure with reduced fabrication cost and enhancing the robustness by relaxed fabrication tolerance.In this paper,the following study is carried out for high-order modeling SIW:1.Four kinds of wideband transition based on the higher mode SIW are proposed in this paper.As the electric field of the slot is similar to the TE₂₀ mode SIW,the first wideband TE₂₀ mode transition is designed by etching a slot on the bottom metal layer to form a slot resonator.Similar to the first transition,the second wideband TE₂₀ mode transition based on the slot line etches a slot line at the middle metal sheet between the two substrate.By embedding several metallic vias in the over-mode cavity,the phase changed and multi-frequency response reached,the third type of TE₂₀ mode is then designed out.The last transition employs the mode conversion technology of rectangular waveguide,using the double curve waveguide to transform TE₁₀ mode to TE₂₀ mode.The four transition all realize the broadband conversion from TEM to TE₂₀ mode.2.Using the wideband TE₂₀ mode transition based on slot as the differential port,a novel single-layered planar magic tee with high mode is proposed.The intrinsic odd symmetry of TE₂₀ mode can produce two out-of-phase output with balanced amplitude and phase.With the embedded arrays of metallic vias,the isolation between the two input is improved.The planar magic tee shows good features and the measured results show good agreement with the simulated ones.3.On the basis of the over-mode transition,we proposed a single-layered planar slot SIW array antenna fed by the TE₂₀ mode SIW.Compared with the traditional dominant mode slot array antenna,the TE₂₀ mode slot array antenna with acceptable electric performance has the merits of not only reducing the number of vias but also doubles the width of SIW,which is useful to relaxing the fabrication tolerance.