An X-band Lens Antenna Based on Metasurface

In this paper, we present a low-cost, high-gain lens antenna operating at X-band that consists of a metasurface-based flat lens and a standard patch antenna. The flat lens comprises three layers, including two outer layers of cross-polarized gratings and a meta-atom-based middle layer. The feed antenna is a standard patch antenna operating in the near field. By designing the meta-atoms appropriately, the lens can achieve a relative phase shift range from 0° to 360°, which is crucial for directing the feed antenna's spherical wavefronts towards the lens. The lens area measures 160 mm × 160 mm, with a separation of 3 mm between the layers. The patch antenna is situated 100 mm away from the lens. Simulation and experimental results demonstrate that the focal length is 50 mm, the beam diameter at the focal point is 10 mm, and the gain is 13.5 dB at 10 GHz. These compact, low-cost lens antennas have the potential to be utilized in environments where space is limited.