基于超表面的紧耦合阵列天线设计

Design of Tightly Coupled Array Antenna Based on Metasurface

设计了一种应用于WiMAX的紧耦合阵列天线。基于超表面解耦原理,设计了一种具有负介电常数和正磁导率的耶路撒冷十字超表面单元。在二单元紧耦合贴片天线上方加载5×6的超表面以减小单元间互耦,矩形贴片上刻蚀一个U形缝隙改善天线的阻抗匹配。阵列天线的尺寸仅为55 mm×74 mm×8.2 mm(0.64λ_(0)×0.86λ_(0)×0.10λ_(0),λ_(0)为3.5 GHz时自由空间的波长),天线单元的间距(边到边的距离)为1.3 mm(0.015λ_(0))。测量结果表明,阵列天线能够工作在WiMAX的3.5 GHz频段,-10 dB阻抗带宽为13.83%(3.23 GHz~3.71 GHz),-18 dB解耦带宽为10.34%(3.3 GHz~3.66 GHz),天线具有良好的辐射特性。

A tightly coupled array antenna for WiMAX application is demonstrated.Based on the decoupling principle of metasurface,a Jerusalem-cross metasurface unit cell with negative permittivity and positive permeability is designed.The mutual coupling between the antenna elements is reduced by loading 5×6 metasurface above the tightly coupled two-element patch antennas,and the impedance matching is improved by etching a U-shaped slot on the rectangular patch.The overall size of the array antenna is 55 mm×74 mm×8.2 mm(0.64λ_(0)×0.86λ_(0)×0.10λ_(0),λ_(0)is the wavelength of free space at 3.5 GHz),the element spacing(edge-to-edge separation)of antenna element is 1.3 mm(0.015λ_(0)).Measured results show that the array antenna can work in the 3.5 GHz frequency band of WiMAX.The-10 dB impedance bandwidth of the array antenna is 13.83%(3.23 GHz~3.71 GHz),and the-18 dB decoupling bandwidth is 10.34%(3.3 GHz~3.66 GHz).Also,a good radiation pattern is obtained.