基于超表面的宽带极化可重构天线
Broadband polarization reconfigurable antenna based on metasurface
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摘要: 为了满足现代通信系统对多功能天线的需求,提出了一种基于超表面的宽带极化可重构天线,天线由上层挖去圆孔的切角正方形超表面和下层双缝微带天线构成。通过围绕天线中心旋转超表面,该天线能够保持在宽阻抗带宽的状态下,实现左旋圆极化(left-hand circular polarization, LHCP)、右旋圆极化(right-handed circular polarization, RHCP)和线极化(linear polarization, LP)等不同极化方式。实测结果表明,超表面天线圆极化(circular polarized, CP)状态的最大阻抗带宽为51.4%(2.99~5.04 GHz),最大3 dB轴比带宽为21.7%(3.73~4.64 GHz);LP状态下最大阻抗带宽为49%(2.97~4.9 GHz),交叉极化鉴别率在20 dBi以上,工作频段内增益均高于7.5 dBi。该天线实现了在宽阻抗带宽状态下CP和LP之间的互相转化,具有良好的工作性能。Abstract: In light of the growing demand for multifunctional antennas in modern communication systems, a broadband polarization reconfigurable antenna loaded with a metasurface is proposed. The antenna comprises an upper layer featuring a circular hole cut out from a chamfered square metasurface and a lower layer consisting of a dual-slot microstrip antenna. The proposed antenna can maintain a broad impedance bandwidth while realizing different polarization modes such as left-hand circular polarization(LHCP) and right-hand circular polarization(RHCP) and linear polarization(LP) by rotating the metasurface around the center of the antenna. The measured results show that the maximum impedance bandwidth achieved for the circular polarization(CP) state of this metasurface antenna is 51.4%(2.99-5.04 GHz), while its maximum 3 dB axial ratio bandwidth reaches 21.7%(3.73-4.64 GHz). For the LP state, the maximum impedance bandwidth is recorded at 49.0%(2.97-4.90 GHz), with cross polarization discrimination exceeding 20 dBi and gain consistently above 7.5 dBi across the operational frequency band. This antenna effectively facilitates transformations between CP and LP within a broad impedance bandwidth and boasts exceptional performance.