基于矩形环加载的UHF频段宽带圆极化天线设计

Design of UHF-Band broadband circular polarization antenna based on rectangular ring loading

提出了一种同时提高探针馈电单层圆极化微带天线的增益带宽、阻抗带宽及圆极化轴比带宽的方法,解决了传统单馈点单层微带天线阻抗及圆极化轴比带宽较窄的问题。基于环形贴片行波圆极化辐射原理,通过在辐射贴片上方加载一方环形金属贴片,该贴片内外环与辐射贴片边缘等距设计,可调参数少,增加了天线阻抗及轴比宽带,提高了天线增益,同时实现低剖面应用。基于此方法,设计了一款应用于某型号的UHF频段宽带圆极化天线,并加工实物。实测结果表明:该天线电压驻波比(VSWR)<2的带宽达到17.2%(370 MHz~440 MHz),轴比(AR)小于3 dB的带宽达到8.4%(395 MHz~430 MHz),天线带宽内主辐射增益约7 dB左右。设计方法对提高单馈圆极化微带天线的轻小型化、宽带技术水平具有重大意义,应用前景广阔。

In order to solve the problems of narrow impedance bandwidth and axis ratio bandwidth of traditional single-fed single-layer microstrip antenna,a method to improve the gain,standing wave and circularly polarized bandwidth of probe fed single-layer circularly polarized microstrip antenna is proposed.By loading a square ring metal patch above the radiation patch based on the principle of circular polarization radiation of annular patch,the inner and outer rings of the patch are equidistant from the edge of the radiation patch,which increases the impedance and axial ratio bandwidth,improves the antenna gain,realizes low profile application.The measured results show that The bandwidth of VSWR<2 is 17.2%(370 MHz~440 MHz),and the 3-dB axial-ratio bandwidth is 8.4%(395 MHz~430 MHz).The gain is about 7 dB within the overlapped bandwidth.This method is of great significance to improve the light and miniaturization and broadband technology level of single-fed circularly polarized microstrip antenna,and has broad application prospect.