基于超表面的宽带低剖面圆极化天线设计

Design of a Wideband Low-profile Circularly Polarized Antenna Based on Metasurface

设计并制备了一种基于超表面的宽带低剖面圆极化天线。该天线由上下两层构成,下层是传统的线极化缝隙微带天线,上层是由方形切角单元构成的超表面。分析了超表面将线极化波转换成圆极化波的工作原理,并对影响天线圆极化带宽的参数进行了优化。仿真结果表明:加载超表面后,不仅使天线辐射圆极化波,还扩展了天线的阻抗带宽,天线相对阻抗带宽达到17%,3 d B轴比带宽达到7.2%。为了验证设计的有效性,加工、测试了天线实物样品,并与仿真结果进行了对比。实测结果与仿真结果吻合较好,说明该天线具备宽带圆极化特性。最终天线整体尺寸仅为0.4λ×0.4λ×0.03λ,天线的剖面较低,非常有利于与载体共形的应用。

A wideband low-profile circularly polarized antenna design based on metasurface is proposed. The antenna consists of twolayers, a metasurface composed of square units with truncated corners is placed on the top layer while using a traditional linearlypolarized microstrip slot antenna as the other one. The metasurface, operational principle of switching linearly polarized wave intocircularly polarized wave is analyzed, and the parameters of the antenna are optimized according to their influence on the band parameters.Simulated results show that the antenna can radiate circularly polarized wave and its impedance bandwidth is broaden byloading metasurface. The relative impedance bandwidth and 3 dB axial ratio bandwidth can reach 17% and 7 . 2 % , respectively.To verify the effectiveness of the antenna design, the prototype of antenna is fabricated and measured, and the measured results agreewell with the simulation, which demonstrates the antenna＇s satisfying property of wideband circular polarization. The antennais favorable for conformal applications as it keeps the 3D size of only 0. 4λ ×0. 4λ ×0. 03λ.