一种宽带高增益圆极化超表面天线

A wideband high-gain circularly polarized metasurface antenna

提出了一种基于超表面的宽带高增益圆极化天线。首先,采用改进的平面螺旋天线作为馈源,螺旋臂宽先增大后减小,既紧密缠绕又缩短了臂长,提升了圆极化性能的同时,缩减了天线的尺寸;然后,设计了一种宽带单层的超材料单元结构,其相位调控范围可达360°,通过周期性排布将其组成反射超表面;最后,将馈源放置在反射面的焦点处,实现高增益天线整体设计。实验结果表明,所提出的天线最高增益可达23.2 dBic,3 dB增益带宽为44%(4.8~7.5 GHz),该频段内阻抗匹配良好(驻波比小于1.5)且满足圆极化特性(轴比小于3 dB),实测结果与仿真结果一致性较好。该天线方向性图稳定,实现了电磁能量的聚集。

A wideband high-gain circularly polarized antenna was proposed based on metasurface.First,an improved planar spiral antenna was utilized as feed.The spiral arm width first increased and then decreased,which both tightly wrapped the arm and shortened the arm length.The circular polarization performance was improved while the antenna size was reduced.Second,a wideband monolayer metamaterial unit structure was designed with a tunable phase of 360°,which was used to form a reflectarray by periodic arrangement.Finally,the feed was placed at the focus of the metasurface to realize the overall design of the high-gain antenna.The experimental results show that the peak gain of the proposed antenna can reach 23.2 dBic,and the gain bandwidth of 3 dB is 44%(4.8-7.5 GHz).The impedance is well matched(VSWR<1.5),and circular polarization satisfies the requirement(AR<3 dB)in this band.The measured results are in good agreement with the simulation ones.The directional pattern of the antenna is stable,and the electromagnetic energy is concentrated.