A Broadband High-efficiency Multifunctional Ultrathin Metasurfaces

This paper proposes a kind of broadband metasurfaces that can independently and finely control the amplitudes and phases with a high efficiency for both reflection and transmission modes. A Fabry-Perot (FP) cavity and a metallic dual-split ring (DSR) polarizer are combined to construct each element of the metasuface that has an ultrathin and planar structure. The forward cross-polarization transmission and backward co-polarization reflection can be switched easily by varying the DSR polarizer. It can offer the arbitrary combination of amplitudes within [0; 1] and phases within the range of [0, 360 degrees] for both transmission and reflection modes. The proposed metasurface was applied to design high-gain low-sidelobe transmitarray antenna (TA) and reflectarray antenna (RA). Comparisons between metasurfaces based on the phase control only and those based on the control of both phase and amplitude are studied. Numerical simulation results verify the described superior performance.