Research On Microstrip Antenna At Ku-Band With Broadband Dual-frequency And Dual-polarized

In this paper, broadband dual-frequency and dual-polarized microstrip antenna at Ku band is described. Three kinds of wideband dual-frequency and dual-polarized microstrip antenna element are proposed and their experimental verifications are completed which based on the classical theory and a deeper study on broadband, dual-frequency and dual-polarization technique of microstrip antenna. From the transmission-line mode theory and simulative results, the bandwidth, isolation and gain characteristics of a microstrip patch element with various structures are analyzed in detail and compared, and an antenna element with the best performance is adopted.Based on the element described, four-element linear array and planar array is designed which adopted anti-phase feeding and dislocation anti-phase feeding technique, respectively. In addition, the technique of anti-phase feeding which suppress cross-polarized is further studied by using the even/odd theoretical analysis. Then we make a comparison with 4-element linear array and 4-element planear array.An Ku-band 4×8-element broadband dual-frequency and dual-polarized microstrip array is developed based on linear array. The measurement results show that the relative impedance bandwidths are 11.62% for horizontal polarization channels and 6.9% for vertical polarization channels, which VSWR less than 1.5 are obtained, respectively. The isolation between two ports is less than -33dB and cross-polarized level is below -20dB, a gain of 21.8 dB and 20.4 dB is achieved for two various band, respectively. Compared with the conventional 4×8-element array, the new structure proposed in this paper has advantages in wideband, isolation and gain characteristics, which has arrived good performance.Finally, we summarize the research of the paper with an outlook for the further researches.