加载超表面的双频紧凑高隔离阵列天线设计

Dual-band compact high isolation array antenna design loaded with metasurface

为了减小极小距离多输入多输出(multiple-input multiple-output,MIMO)天线之间的相互耦合,设计了一种极紧凑的高隔离度的双频MIMO贴片天线,谐振频率分别为2.45 GHz和3.5 GHz。该MIMO天线由两个对称的双层U型槽贴片天线组成,其中边与边的距离为0.5 mm(0.004λ_(0),λ_(0)为中心频率2.45 GHz时的自由空间波长)。利用不同宽度的双层金属线切割对作为超表面单元,该超表面体积紧凑,可以显著降低天线单元之间的相互耦合。仿真和测量结果表明:在天线工作频段2.4~2.5 GHz和3.4~3.6 GHz范围内,单元间的隔离度可以提高到30 dB以上,并且两个天线端口阻抗匹配良好,同时在低频段的总效率提高了9%左右;两天线间的包络相关系数(envelop correlation coefficient,ECC)在2.45 GHz时由0.33降到0.01,在3.5 GHz时由0.09降到0.006,所设计天线具有良好的辐射性能。

In order to reduce the coupling between very small distance multiple-input multiple-output(MIMO)antennas,an extremely compact dual-band MIMO patch antenna with resonant frequencies of 2.45 GHz and 3.5 GHz is designed.The MIMO antenna consists of two symmetrical double-slot U-slot patch antennas with an edge-to-edge distance of 0.5 mm(0.004λ_(0),λ_(0)is the free space wavelength at a center frequency of 2.45 GHz).Double-layer wire cut pairs of different widths are used as metasurface elements,which are compact and can significantly reduce the coupling between antenna elements.Through simulation and measurement,in the antenna operating frequency band 2.4–2.5 GHz and 3.4–3.6 GHz range,the isolation between the units can be increased to more than 30 dB,and the impedance of the two antenna ports is well matched,at the same time,the total efficiency in the low frequency band is increased by about 9%,and the envelop correlation coefficient(ECC)between the two antennas is reduced from 0.33 to 0.01 at 2.45 GHz,at 3.5 GHz,it drops from 0.09 to 0.006,which has good radiation performance.