折尾宽波束圆极化天线的设计

Design of Folded-tail Wide Beam Circularly Polarized Antenna

介绍一种应用于卫星通信上的天线,该天线是十字交叉振子天线的变形天线,要求工作在圆极化方式下,具有比较宽的或者是赋形的辐射方向图,结构简单紧凑,且工作可靠。该折尾天线直接由同轴线馈电,当两副正交振子的自阻抗不同时,被激励起来的电流相位就不同。控制自阻抗的大小,可以实现90°的相差,从而可实现圆极化,并且在末端弯折以提高圆极化性能。仿真显示,当反射板距离天线振子0.45λ时,波束宽度达到150°,驻波在1.2以下,电性能良好。

A kind of antenna used in satellite communications is described. It is a modify antenna with two orthogonal dipoles, requires that these antenna works under the mode of circular polarization way in general, and needs wide beam or eonforreal radiation patterns,configuration of the antenna structure compact,and can simplely reliably to work. The folded - tail antenna is feed by the cable directly, when the self - impedance of the two orthogonal dipoles is different, the excited current phase is different. Controlling the self- impedance,90° phase difference can be realized, then circular polarization is achieved, folding at the end can enhance the circular polarization performance. The simulation and measurement show that when the distance between the dipoles and reflector is 0.45λ,width of the beam reach to 150°,the VSWR is under 1.2,the performance is all right.