Fan-Shaped Multibeam Metasurface Lens Antenna for High Crossover Levels and Stable Radiation Gain

A fan-shaped multibeam antenna based on a metasurface (MS) lens is first proposed and validated in this letter. It features stable radiation gain and high beam-crossover levels that are attractive in high-quality beam-scanning applications. A simple multiport pillbox antenna is employed as the source antenna, while an MS lens is placed above it with an air gap for beamforming. The proposed MS antenna targeting 5G millimeter-wave band has a −10 dB impedance bandwidth from 26.9 to 29.9 GHz. It can generate five beams with a scanning range of ±30°. Remarkably, the beam-crossover levels are higher than −1.9 dB at the central frequency. The gain variation for each beam is within 1 dB for a 12° coverage range and 3.5 dB for the whole ±30° angle coverage range. Compared with previous reports, the proposed MS antenna shows great advantages in terms of electric performance and physical properties.