Aperture Efficiency Improvement by Reflectionless Metasurfaces for Large-Aperture Antennas

We design an impedance-matched reflectionless metasurface to manipulate the aperture phase of an X-band large-aperture slot array antenna. By proposing a design procedure for large-area metasurfaces in practical applications with preparing a database that relates the propagation characteristics of unit cells with their physical structures, we design a large-area non-periodic reflectionless metasurface consisting of 200×34 unit cells. A gain enhancement due to an aperture efficiency improvement by the metasurface is experimentally demonstrated at 9.41 GHz.