设计了一种GPS/北斗频段的小型化具有宽带宽波束宽轴比特性的平面四臂螺旋天线。该天线分为馈电网络和辐射体两个部分,馈电网络采用平行双线差分馈电,引入180 o相位差,从而减少了一级功分器,使馈电网络的平面尺寸减小一半;辐射体部分采用平面结构,每个天线臂采用倒F 形式,逆时针旋向印制在介质基板上,中间增加了空气层来增大天线的增益,这种平面结构大大降低了天线的高度。馈电网络的信号通过馈电金属柱传输至辐射体。通过电磁仿真软件Ansoft HFSS 仿真和优化,并制作了实物。测试结果表明:中心频率1. 57 GHz 处的相对带宽(VSWR<1. 5)达到12. 7% ,增益达到3. 38 dBi,俯仰面的半功率波瓣宽度为110 o,俯仰面的3 dB 轴比宽度为132 o,方位面的不圆度为0. 5 dB。

A compact broadband wide beam and wide axial ratio planar quadrifilar helix antenna which works in the frequency band of GPS/ COMPASS is designed out. It consists of feed network and radiator. A 180 o phase difference is attained through the feed network of the parallel double transmission line, which reduces the dimension of the feed network by half. The plannar structure of the radiator consisted of four arms which are inverted F antenna and printed on the surface of the dielectric substrate in the counter clockwise direction reduces the height of the antenna. The novel antenna is simulated and optimized by the EM simulation software Ansoft HFSS,then its practical object is fabricated and tested. The measured results show that the antenna has a good performance of relative bandwidth (VSWR<1. 5) in the center frequency of 1. 57 GHz as great as 12. 7% , a gain of 3. 38 dBi, half power beamwidth of 110 o and 3 dB axial ratio of 132 o on the meridian plane, non鄄circularity of 0. 5 dB on the equatorial plane.

TN82