基于后向辐射抑制的低剖面圆极化环天线研究

Research of low profile circularly polarized loop antenna based on backward radiation suppression

为了适应现阶段可移动终端的小型化发展趋势,设计了一种结构紧凑的低剖面高前后比圆极化环天线,可覆盖BDS-B1和GPS-L1两个工作频段。天线的辐射体采用环形贴片,使用两个不同面积的耦合馈电枝节给天线耦合馈电,实现天线的圆极化辐射。另外,深入探讨了寄生环的后向辐射抑制机理,使天线得以在结构紧凑的基础上实现了天线的高前后比,并且可实现天线的前后比与辐射效率之间的灵活调控。测试结果表明,在工作频带内,所设计的天线具有10 dB以上的前后比,实际增益不低于3.25 dBi,天线在3-dB轴比带宽内具有不少于3.19 dBic的右旋圆极化增益。此外,所设计的天线辐射器尺寸为0.148λ_(0)×0.148λ_(0)(λ_(0)为真空波长),整体尺寸为0.236λ_(0)×0.236λ_(0)×0.028λ_(0),可适用于小型化程度较高的终端设备中。

In order to adapt to the development trend of miniaturization of mobile terminals at present,a compact circular polarization ring antenna with low profile and high front-to-back ratio is proposed in this paper,covering the two operating bands of BDS-B1 and GPS-L1.The radiator of the antenna is a loop patch,and two coupled feeding branches with different areas are used to feed the antenna to achieve circular polarization radiation.In addition,the mechanism of backward radiation suppression of the parasitic loop is deeply discussed,which enables the antenna to achieve a high front-to-back ratio on the basis of compact structure,and the exchange between the front-to-back ratio and the radiation efficiency can be realized.The measured results show that in the operating frequency band,the designed antenna has achieved a front-to-back ratio of more than 10 dB,the realized gain is higher than 3.25 dBi,and the antenna has a right-handed circular polarization gain of not less than 3.19 dBic in the 3-dB axial ratio bandwidth.In addition,the size of the designed antenna radiator is 0.148λ_(0)×0.148λ_(0)(λ_(0) is the vacuum wavelength),and the overall size is 0.236λ_(0)×0.236λ_(0)×0.028λ_(0),which can be applied to the terminal equipment with high degree of miniaturization.