X-Band Phase-Gradient Metasurface for High-Gain Lens Antenna Application

We propose a high-gain transmitting lens antenna by employing layered phase-gradient metasurface (MS). The MS is engineered to focus the propagating plane wave to a point with high efficiency. An X-band patch antenna is placed at the focal point of the MS as a feed source, and then the quasi-spherical wave emitted by the source is transformed to plane wave. Due to the successful conversion of quasi-spherical wave to plane wave, the beam width of the patch antenna has been decreased 66° and the gain has been enhanced 11.6 dB. The proposed lens antenna not only opens up a new route for the applications of phase-gradient MS in microwave band, but also affords an alternative for high-gain antenna.