Study On Broadband Short Backfire Antenna Applied In Millimeter-Wave Band

In wireless communication systems,the applications of millimeter-wave(MMW)antennas become more and more extensive with the opening of 5G era.As the complexity of wireless communication transmission paths increases,multipath attenuation is becoming more and more serious.To meet the 5G application demands,broadband and high-gain MMW antennas have attracted much attention.In view of the current challenges and development trend of MMW antennas,this paper,relying on the substrate integrated waveguide(SIW)technology,carried out the design of several MMW antennas and related structures:1.A broadband MMW differential-fed dual-polarized magneto-electric dipole antenna.The differential-fed technology has the advantages of strong common mode rejection,low noise and low cross polarization.At the same time,the dual-polarized technology can be used to solve the multipath fading problem.The fusion of these two technologies can make the antenna have better performance.Therefore,based on these two technologies,a differential-fed dual-polarized magneto-electric(ME)dipole antenna is presented in this thesis.The designed ME dipole antenna operates in MMW band with good performance,including wideband,high gain,and symmetrical radiation pattern.In addition,due to the use of SIW technology,the ME dipole antenna features with simple structure and easy integration,which can meet most MMW working environment.2.A broadband MMW transition of air-filled rectangular waveguide to differential substrate integrated waveguide.The air-filled rectangular waveguide(RWG)and the substrate integrated waveguide(SIW)are often used simultaneously in the design of antennas.However,the two structures cannot be directly connected,and it is necessary to add a transition structure between the two structures.At the same time,the performance of the transition structure has a particularly large impact on the millimeter-wave antenna.Besides,there are not many differential transition structures proposed at present.Therefore,designing the differential transition structure of broadband RWG and SIW has practical application value.The differential transition structure is designed to realize the widening of the bandwidth of the transition structure by using the SIW resonator.At the same time,the impedance matching of the H-type slot and the inductive window are used together to achieve the performance of the broadband,and the signal amplitude of the output is consistent and the phase difference is stable.3.A broadband SIW-based MMW short backfire antenna based.The traditional short backfire antenna has the advantage of high gain,but suffers with narrow bandwidth.Currently,several advanced short backfire antennas have been realized with broadband performance,but with complicated structures.In addition,there are few researches on short backfire antennas using SIW technology.Therefore,a broadband MMW short backfire antenna using SIW is proposed.The proposed wideband magneto-electric dipole antenna is used as the feed of the short backfire antenna,and SIW circular cavity and air circular cavity are added to improve the performances.So that the proposed short backfire antenna can have broadband and high gain.At the same time,it has the advantages of simple structure and easy integration.