基于相位梯度超表面的高增益天线设计

Design of High-Gain Antenna Based on Phase Gradient Metasurface

根据广义Snell反射定律,相位梯度超表面可在其表面形成额外的平行波矢分量,从而对电磁波的反射进行调控。如果构成反射超表面单元的相位差按照抛物面分布,那么就可以实现对垂直入射电磁波的聚焦;相反,在超表面焦点处放置辐射球面波的馈源,球面波经超表面反射可以得到平面波,从而提高馈源增益。本文基于有相位梯度的单元,设计了由13×13个单元构成的二维反射相位梯度超表面,并在其焦点处放置贴片天线,构成反射面天线。仿真和测试结果都表明,贴片天线辐射的球面波经超表面反射后得到了平面波,天线的增益达到20 d B,比贴片天线提高了11.7 d B。

According to the generalized Snell＇s law for reflection,an extra parallel wave vectors can be formed on phase gradient metasurface and will induce the reflection of microwave. If the unit cell follows the parabolic profile to constitute the metasurface,the focusing of normal incidence can be realized;On the contrary,put a feed source which radiates spherical wave at the focal point,plane wave can be got by the reflection of metasurface,improving the gain of the feed source. Based on the phase gradient unit cell,this paper designs a two dimensional phase gradient metasurface by 13×13 units and put a patch antenna at focal point to constitute the reflector antenna. The results of simulation and testing show that spherical wave turns into plan wave by the reflection of metasurface,the reflector antenna achieves peak gain of 20 d B,in which the gain has been enhanced by 11.7 d B.