基于单层反射超表面的宽带圆极化高增益天线设计  

Broadband circularly polarized high-gain antenna design based on single-layer reflecting metasurface

作　　者：李唐景 梁建刚[1] 李海鹏[1] 

机构地区：[1]空军工程大学防空反导学院,西安710051

出　　处：《物理学报》2016年第10期83-89,共7页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:61372034)资助的课题~~

摘　　要：基于Pancharatnam-Berry相位原理,设计了一种宽带圆极化反射聚焦超表面并将其应用到提高天线增益中.首先提出了一种变形十字超表面单元,在11—16 GHz频带范围内能够实现高效同极化转换,并基于该单元构建了宽带反射聚焦超表面.仿真结果表明,垂直入射的右旋圆极化平面波宽带聚焦效果明显.然后利用单向阿基米德螺旋天线对超表面进行照射,其辐射的球面波经超表面反射后得到了近平面波,有效地提高了天线的增益.最终对所设计的天线系统进行加工并测试,结果表明系统的-1 d B增益带宽达到25%(12.5—16 GHz),在该频带范围内峰值增益均高于19 d Bc且轴比小于3 d B.此外,在12—15.5 GHz范围内天线口径效率均超过50%.According to the Pancharatnam-Berry phase principle,a single-layer reflecting element is proposed for steering the phase of the electromagnetic wave.The structure of the element is composed of metabolic cross wire and copper ground sheet,which are separated by an FR4 dielectric substrate with a thickness of 3 mm.When the incident wave is circularly polarized,different rotary angles of the element are used to achieve the co-polarization reflection with high efficiency in a broadband of 11–16 GHz.In the design of the focusing metasurface,the phase compensation for forming a constant aperture phase is provided by the individual reflected element with a different rotated angle.Remarkably,the size of the element is only 5 mm（0.23λ0）,and then it can be more accurate to control the phase of the array.The focusing metasurface is composed of 15×15 elements with a focal length of 30 mm at 13.5 GHz.The designed sample is simulated in CST Microwave Studio.The results show that the incident circularly polarized plane wave is well transformed into a spherical wave in the band from 11 to 16 GHz,and the focal length is around 30 mm.For further application,a unidirectional Archimedean spiral antenna is located at the focal point of the metasurface.According to the reversibility principle of electromagnetic wave propagation,the spherical wave radiated by the feed antenna is converted into a plane wave by the reflecting metasurface,so that the antenna gain is remarkably enhanced.Through adjusting the distance between the feed antenna and the focusing metasurface,we find that 28 mm is the best distance.Finally,the feed antenna and the metasurface are fabricated,assembled and measured.Numerical and experimental results are in good agreement with each other,showing that the-1 d B gain bandwidth of the high-gain antenna is 12.5–16 GHz,and in this band the peak gains are all over 19 d Bc and the axial ratio is better than 3 d B.In addition,the aperture efficiencies are more than 50% in the band from 12 to 15.5 GHz,especially t

关 键 词：超表面 宽带 圆极化 高增益 

分 类 号：TN820[电子电信—信息与通信工程]