馈电同轴芯径对微带天线性能的影响

针对同轴线馈电的微带天线,建立了等效电路模型。该等效电路表明,馈入到微带天线内部的导体直径直接影响天线的输入阻抗。为此设计了单频圆极化微带天线,采用电磁计算软件HFSS仿真计算了不同馈电芯径对天线参数的影响,验证了该理论。同时设计了双层介质的双频微带圆极化天线,采用同一个馈点馈电,上层微带介质中馈电导体的直径与下层微带介质中馈电导体直径不同。通过HFSS软件的优化仿真,得到了对应于两个不同频段的最优上下层馈电导体直径,获得了最佳的驻波。研究表明,对于单频和双频微带天线,通过优化馈入到介质中导体的直径可以改善天线的驻波特性。

Effect of the Core Diameter of Feed Coaxial Cable on the Performances of Microstrip Antennas

The equivalent circuit model is presented for a Microstrip Antenna(MSA) with coaxial cable feed,which shows that the diameter of fed line conductor embedded in the MSA's dielectric material have a direct influence on input impedance.And then a single frequency circular polarized MSA with single coaxial cable feed is designed and simulated with HFSS for different core diameter of feeding cable, and the simulation results show that the performances of MSA can be improved obviously by optimizing the core diameter.Furthermore,a dual frequencies circular polarized MSA with single coaxial cable feed is designed,where the antenna has both upper and lower dielectric and the fed line conductor diameters in both materials are different from each other.By simulation with HFSS,both optimal diameters are obtained and the antenna gets an optimal VSWR at two different bands.The above work proves that antenna VSWR can be get improved by optimizing the feed line conductor diameter embedded in the dielectric material for both signal and dual frequencies MSAs.