Design And Analysis Of Multi-Polarized Dielectric Rod Antenna Based On K/Ka Band Broadband OMT

In order to meet the growth of communication capacity and the requirements for the miniaturization of communication systems,wideband multi-polarized planar antennas have attracted wide attention.Wideband multi-polarized antennas have the characteristics of wider relative bandwidth,high gain,and reusable polarization.It has important application and research significance in the fields of satellite communications,radio astronomy and electronic reconnaissance.This paper introduces some basic theories involved in the design of orthogonal mode converter and dielectric rod antenna,including the transmission mode s of rectangular waveguide,cut-off frequency,single-mode working bandwidth and the distribution of tube wall current when TE10 wave is transmitted in the waveguide;the equivalent circuit of ridged waveguide,working modes and specific impedance;the working principle,working mode,isolation and matching method of the orthogonal mode converter,the principle and design method of the substrate integrated waveguide.On this basis,two kinds of K/Ka band wideband multipolarized planar dielectric rod antennas are designed.The designed multi-polarized dielectric rod antenna based on K / Ka band wideband OMT improves the working bandwidth of the antenna by introducing ridge waveguide,which restrains the phenomenon of beam splitting of the antenna pattern at high frequency.The OMT with symmetrical structure of boifot junction can effectively improve the working bandwidth of the antenna.The rectangular dielectric b lock and dovetail achieve good impedance match between the air filled square ridge d waveguide and the free space,and the two ends of the conical dielectric rod improve the gain of the antenna.The dual polarization band of the antenna is 21-34 GHz,and the gain is 10.2-15.9 d Bi.The antenna achieves circular polarization in the frequency range of 29.9-30.2 GHz.The multi-polarized dielectric rod antenna based on K/Ka band wideband SIW OMT realizes the matching and transition from SIW with rectangular inter face to SIW with square interface through stepped impedance converter to improve the working bandwidth of vertical polarization.Two kinds of coaxial ridged SIW converters are designed to feed two polarization ports of the OMT.Two pieces of quadrangular dielectric rods are loaded on the front end of the SIW OMT to guide the radiation and improve the antenna gain.The antenna achieves dual polarization in the frequency bands of 20.9-22.7 GHz and 30.1-33.7 GHz,with a gain of 10.1-16.1 d Bi.The antenna achieves circular polarization in the frequency range of 21.7-21.9 GHz and 31.4-31.6 GHz,with a gain of 10.4-15.9 d Bi and an axial ratio of less than 3 d B.Two kinds of K/Ka band wideband multi-polarized dielectric rod antennas have realized planarization design,and the rotational symmetry of the pattern is very good,which is suitable for satellite communication system.In this paper,analysis methods of S-parameter extraction and comparison of four port network based on the principle of dual polarization rea lized by OMT,the relationship between the axial ratio of circular polarization and the phase difference of electric field,equivalent plane element traveling wave array model for antenna to realize directional radiation are proposed.The proposed analysis methods explain the working principle of the multi-polarized antenna proposed in this paper,and can be used to guide the design of dual-polarized antenna,circularly polarized antenna and directional radiating antenna.