Millimeter-wave Circularly Polarized Slot Traveling Wave Antenna Based On Integrated Substrate Gap Waveguide

With the advent of the 5G era,the research on millimeter wave technology has become more and more in-depth,and it has also put forward higher requirements for wireless communication systems in the millimeter wave band.As an extremely important component of the RF front-end of the communication system,the antenna is also developing in the direction of miniaturization,circular polarization,low cost,integration,and broadband.In recent years,the new waveguide structure integrated substrate gap waveguide?ISGW?provides a new idea for antenna design in the millimeter wave band.In this paper,the waveguide structure is used to study the broadband and array applications of millimeter-wave circularly polarized slot-wave antennas.The main work is as follows:?1?A circularly polarized slot traveling wave antenna fed by ridge ISGW with two-layer structure is proposed.The antenna is composed of two narrow slits which are cleverly combined as a circularly polarized radiator,and the slit is coupled and fed by the ISGW with a ridge,thereby realizing the radiation of the circularly polarized wave.The mechanism of the left/right circular polarization of the antenna is analyzed in detail through the equivalent circuit of the slot and the electric field distribution,and the design flow of the structural parameters is given.The simulation results show that the relative axial ratio bandwidth of the antenna is 26₈%,the relative impedance bandwidth of-lOdB is 70.2%,and the maximum gain is 6.4dBi.?2?A circularly polarized slot traveling wave antenna with three-layer microstrip ISGW is proposed.The mechanism of the circularly polarized radiator and the circular polarization of the antenna is the same as that of the above antenna,and the difference is that the microstrip type ISGW is used for coupling feeding of the slit,thereby realizing the radiation of the circularly polarized wave.The simulation results show that the relative axial ratio bandwidth of the antenna is 36.1%,the relative impedance bandwidth of-10dB is 58.2%,and the maximum gain is 5.8dBi.Finally,the performance of the antenna was verified by processing test.?3?A circularly polarized slot traveling wave array antenna based on ISGW is designed using the three-layer microstrip ISGW antenna element mentioned above.The optimization of the antenna unit pattern is realized by means of series array,and a narrow beam,low sidelobe and high gain circularly polarized antenna array are obtained.The antenna array consists of 2×7 rectangular narrow gaps to form a circularly polarized radiator.The microstrip type ISGW is used to cross-feed the gap,and the left/right circularly polarized wave radiation is realized by the change of the feed port..The simulation results show that the array antenna-10dB relative impedance bandwidth is 41.8%,the 3dB relative axis ratio bandwidth is 16.2%,and the maximum gain is 13dBi.