A Wideband High-Gain Conical Short Horn based on a Metasurface-corrected Lens

A wideband high-gain conical short horn with a wide flare angle is developed by loading a ultrathin planar metasurface lens on the aperture. The lens that exhibits wideband high-efficiency transmission and phase changes is composed of two identical dielectric layers, a metallic cross-dipole in the middle and two identical orthogonally-oriented gratings on the two sides. By placing the metasurface lens on the horn aperture, the linearly-polarized spherical wavefront inside the horn can be converted to be a planar one, resulting in high gain. An example compact horn operating at 30 GHz is given. Simulations show an impedance bandwidth of over 30.5%, a peak gain of 28.9 dBi and an aperture efficiency of 49.4%.