宽频多模态涡旋电磁波超表面设计

Design of Wideband Multi-mode Vortex Electromagnetic Wave Metasurface

针对超表面产生OAM(轨道角动量)涡旋电磁波模态单一的问题,提出了一种宽频带多波束多模态OAM波束超表面的设计方法。采用方形开口环结构,优化几何参数,通过开口尺寸的变化构建8个3-bit数字编码单元。利用矢量叠加原理,由产生单一模态OAM波束所需的相移得到多模态涡旋波束的超表面相位分布。采用天线阵列理论可直接求得超表面的远场方向图,并与全波仿真结果进行对比。研究结果表明,利用该方法设计的超表面,能够同时生成多个OAM波束,并且每个波束的辐射方向和OAM模态可根据实际需求进行设定。设计的超表面还具有电尺寸小、剖面低和工作频带宽等优点,在无线通信领域具有广泛的应用前景。

In order to solve the problem of mono-mode orbital angular momentum(OAM) vortex electromagnetic wave generated by metasurface, a design method of multi-beam multi-mode OAM beam metasurface is proposed. By adopting a square split ring structure and optimizing parameters, 3-bit digital encoding units are constructed. Using the vector superposition principle, the metasurface phase distribution of the multi-mode vortex beam is obtained from the phase shift required to generate the single-mode OAM beam. The far-field pattern of the metasurface can be directly obtained through the antenna array theory, and the results are analyzed and compared with the full-wave simulation results. The research results show that the metasurface designed by this method can generate multiple OAM beams at the same time, and the radiation direction and OAM mode of each beam can be set according to actual needs. The design method is flexible and simple. Multi-beam and multi-mode vortex electromagnetic waves are simultaneously emitted by a single metasurface, which has great application prospects in the fields of Wireless communication.