Research On 128-element Microstrip Array Antenna At Ku-Band With Broadband Dual-frequency And Dual-polarized

The research of some problems sbout the theory and the design of broadband microstrip power divider, 128-element broadband dual-frequency and dual-polarized microstrip array antennas and cavity diplexer in Ku-band is described in this paper.Firstly, three kinds of Wilkinson microstrip power dividers are introduced, including even Wilkinson microstrip power divider, uneven Wilkinson microstrip power divider and broadband Wilkinson microstrip power divider. A Wilkinson power divider with the frequency range from 11GHz to 15GHz is designed, The measurement results show that a good match at input port ( VSWR ? 1.5) and more than 15dB isolation between two output port.Based on the theoretic analysis, 128-element broadband dual-frequency and dual-polarized microstrip array antennas is mainly researched. Aperture coupling feed , anti-phase feeding and single-layer microstrip patch structure are applied to design this microstrip antenna array。It consists of four 4×8-element broadband dual-frequency and dual-polarized microstrip array connected by a one divides into four even Wilkinson microstrip power divider, and using CST simulation software modeling simulation. The measurement results show that the relative impedance bandwidths are 10.7% for horizontal polarization channels and 5.02% for vertical polarization channels, which VSWR less than 1.5 are obtained, respectively. The isolation between two ports is less than -28dB and cross-polarized level is below -18dB, a gain of 26.2 dB and 24.1 dB is achieved for two various band, respectively. Both the simulated and measured results show that antennas array designed have good performance and achieve the need of design on the whole.Then, the design of a Ku-band cavity diplexer with an E-plane T-junction is presented by the establishment of the equivalent circuit model, and the design process is described. The fractional bandwidths for two bands are 0.77% and 0.75%. The optimized return losses less than -20dB and insertion losses are better than 1.2 dB for the two filters with less than -55 dB isolation.Finally, we summarize the research of the paper and propose some needed improved problems ulteriorly.