共口径双圆极化微带天线

针对圆极化天线轴比带宽较窄的问题，设计了一种由两个威尔金森功分器和两个环形电桥馈电的四馈双圆极化微带贴片天线。由于馈电网络不同端口在馈电时其输出信号相移方向相反, 因此可以辐射左、右旋圆极化波。双圆极化馈电网络具有结构简单、性能可靠特点。辐射贴片采用顶点相对的4个三角形贴片加载T形枝节, 并采用背馈的形式实现了天线紧凑的结构。在2.4~2.48 GHz频段内天线实测中心频点S₁₁小于-15 dB, 端口1的左旋圆极化轴比小于2 dB, 端口2的右旋圆极化轴比小于1.5 dB, 与同类型相近尺寸的天线相比具有较宽的轴比带宽。对其远场辐射方向图进行了仿真和测试, 结果表明这种四馈电结构改善了辐射方向图的对称性和轴比。

Co-aperture dual circularly polarized microstrip antenna

In order to solve the problem of narrow axial ratio bandwidth of circularly polarized antenna, a four-fed dual circular polarization microstrip patch antenna which is fed by two Wilkinson power dividers and two ring bridges is designed. The phase shift direction of the output signal is opposite when the feeding network is fed by different ports, so it can radiate left-handed or right-handed circular polarized waves. The dual circular polarization feed network has the characteristics of simple structure and reliable performance. Four triangular patches with opposite vertices are used to load T-shaped branches, and the back-fed structure of radiation patch realizes the compact structure of the antenna. The prototype antenna is fabricated and tested in the frequency band of 2.4~2.48 GHz, the measured center frequency point S₁₁ is less than -15 dB, the left-handed circular polarization in port P_in1 is less than 2 dB, and the right-handed circular polarization in port P_in2 is less than 1.5 dB. Compared with the same type of similar size antenna, it has a wider axial ratio bandwidth. The radiation pattern is simulated and tested and the results show that the four-fed structure improves the symmetry and the axial ratio of radiation pattern.