一种基于超表面的低剖面宽带透镜天线

A low-profile wideband lens antenna based on metasurface

提出一种新型的基于超表面的低剖面宽带高增益透镜天线,该透镜采用宽带的电偶极子天线作为馈源,设计中心频率工作在10GHz.针对超表面透镜在不同位置的折射率的需求,同时提出了一种新型的非谐振超材料单元,该单元由三层介质板组成,中间一层是印有十字形带状线的双层印刷板.通过改变上下两层介质的介电常数,可以达到不同的折射率变化范围,从而实现透镜的中间层和阻抗匹配层对折射率的需求.所提出的透镜天线设计方法可以获得21 dBi的最高增益以及58%的-10dB阻抗带宽.更重要的是所提出的具有高折射率的超材料单元可以实现只有0.32λ0的透镜厚度,大大减小了透镜的剖面.最后进行了加工实验,对所提出的方法和仿真结果进行了验证,实验结果表明,透镜天线的实测带宽、方向图和增益都与仿真理论结果有较好的吻合度.

This paper proposes a new low-profile high-gain wideband gradient refractive index （GRIN） lens fed by a magnetic-electric （ME） dipole antenna. As a constituent part of this lens, a novel sub- wavelength nonresonant metamaterial unit cell composed of 3-layer substrates is also proposed. By apply- ing Rogers 5880 and air as the top and bottom layers, high and low refractive indexes can be achieved for realizing the core layer and impedance matching layer （IML）, respectively. Therefore, the proposed lens antenna can exhibit high gain of 19 dBi and -10 dB bandwidth of 58% （6.8-12.4 GHz）. Moreover, due to the high refractive index which is realized by the bilayer cross-shaped rings meta unit cell, the total thickness of the lens is 0.32λ0, where λ0 is the wavelength at 10 OHz.