| Ka-band high-gain dual-circular-polarized planar antenna has the advantages of strong anti-interference ability,easy polarization matching and so on.It has a broad application prospect in the field of satel ite communication.However,by studying the existing Ka-band high-gain dual-circularly-polarized planar antenna,it is found that there are still problems of high profile and narrow bandwidth,which limits the applicatio n scope.Based on the basic theory of linear polarized waves synthesizing dual-circularpolarized wave,the dissertation studies the following aspects: reducing the profile of dual-circular-polarized antenna and expanding the bandwidth of dual-circular-polar ized antenna.In order to solve the problem of high profile of the existing Ka-band high-gain dualcircularly-polarized planar antenna,a new low-profile dual-circular-polarized planar antenna is proposed by combining the reconfigurable cross polarized gate with the ridge waveguide slot antenna.The antenna utilizes a reconfigurable cross-shaped polarizat io n gate as an anisotropic material to positively decompose the line polarization wave and form a ±90° phase difference.It does not need a circular polarizer in the form of a metal cavity,thus reducing the profile.An 8×12-element Ka-band high-gain dual-circular l ypolarized planar antenna is designed,and its profile height is only 16 mm.The maximum gain of this antenna is more than 25.5dBi.Within 8% of the relative bandwidth,the axial ratio of the high-gain dual-circularly-polarized planar antenna is better than 3dB,and the reflection coefficient of the input port is less than-10 dB.In order to solve the problem of narrow bandwidth and high profile of the existing Ka-band high-gain dual-circularly-polarized planar antenna,a new dual-circularpolarized planar antenna with wide band and low profile is proposed by combining the complementary phase shifters and the dual-polarized power divider.The antenna uses complementary phase shifters to reduce the height of the profile and a dual-polarized power divider to expand the impedance bandwidth.Firstly,the feasibility of the scheme is verified by the fabrication and measurement of the 2×2-element dual-circular-polar ized planar antenna.Then,a 32×8-elemennt Ka-band high-gain dual-circularly-polar ized planar antenna is designed.The height of the section of the antenna is only 31 mm,the maximum gain of the simulation is more than 32 dBi,and the relative bandwidth is 28%.In this bandwidth,the dual-circular-polarized axis ratio of the antenna is less than 1.5dB,the reflection coefficient of the two input ports is less than-10 dB,and the isolation is greater than 19 dB. |
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