Achieving Wideband Beam-Splitting with an Ultrathin Discrete Huygens' Metasurface

We propose the design of a Huygens' metasurface whose elements can realize stable reflection characteristics from 21 GHz to 30 GHz (37% bandwidth). The proposed metasurface features two markedly different elements which provide a reflection phase difference of 180
^°
±37
^°
over the aforementioned band. This design methodology allows one to broaden the bandwidth of various metasurface designs that rely on a variation of reflection coefficients. As a simple example, we demonstrate a metasurface that reduces the reflectance of a normally incident electromagnetic (EM) wave by redirecting the energy into oblique scattering directions. A wideband beam splitter is hence designed with very thin substrate thickness and utmost simplicity. This work paves way to the design of wideband Huygens' metasurfaces.