Research Of High Performance Half-mode And Folded Substrate Integrated Waveguide Passive Components

Microwave passive components are key components in microwave circuits and systems,which are widely used in wireless communication systems.With the rise and gradual popularization of the fifth generation mobile communications(5G),the development of microwave passive components has also attached more and more attention.As a planar waveguide technology,half-mode SIW(HMSIW)and folded SIW(FSIW)have attached much attention due to its excellent performance.Nowadays,passive components are required not only to achieve the characteristics of broadband and low loss,but also to have the advantages of miniaturization,low cost and easy integration.The research and design of high performance HMSIW and FSIW passive components have very important application value and scientific significance for the development of modern wireless communication systems.In this paper,based on HMSIW and FSIW,some high-performance HMSIW-and FSIW-based microwave passive components like 90° directional couplers,phase shifters,and 180° directional couplers have been designed and studied.The main research in this work includes the following aspects:(1)Based on the theory of waveguide narrow wall directional coupler and microstrip patch coupler,an HMSIW and microstrip rectangular patch hybrid integrated coupler has been presented,it can connect to both microstrip circuit and HMSIW devices directly,which provides a solution for system integration;The fractional bandwidth(FBW)of the hybrid directional coupler is 21%,the amplitude imbalance is less than 1d B and the phase imbalance is less than 4°.Moreover,it has a more compact and simple structure and is easy to fabricate.(2)A FSIW wide-band phase shifter is designed by loading complementary open-loop resonators(CSRRs)on the middle metal layer of FSIW.It can provide 39% broadband phase shift compared to a equal-length FSIW transmission line.In addition,the slow wave effect of CSRR reduces the length of the phase shifter,making the phase shifter more compact and easier to integrate with other FSIW devices.Meanwhile,the insertion loss of the proposed phase shifter is lower due to the closure of the FSIW structure.(3)Based on the phase shifter proposed in(2),a FSIW 180°directional coupler has been proposed by applying it to a FSIW 90°directional coupler.The measured results show that the return loss of the coupler is better than 17 d B,the isolation is greater than 19.5d B,the power balance is-4.6±0.5 d B in 10.5-13.6 GHz with an FBW of 26%,and the output phase difference is180°±5°from 10.3 to 14.4 GHz.