High-gain multiband metasurface antenna with frequency and polarization reconfigurability for millimeter-wave applications

This paper presents what we believe to be a novel high-gain metasurface antenna design supporting multiband operation and multiple linear polarizations. The proposed structure integrates a Fabry-Pérot (F-P) cavity with a dual-layer metasurface transmit array and a wideband stacked patch feeder. A key innovation is the introduction of the equivalent focal length of the F-P cavity, along with a simplified design formula, to optimize the metasurface arrangement. To reduce the metallic area and minimize the interaction between the metasurface and feeder, a unique unit cell design featuring six rectangular elements is employed, oriented vertically, horizontally, or at ±45° angles to support polarization diversity. The feeding structure integrates a wideband stacked patch antenna with a surface wave suppression metamaterial ground plane, enabling a compact design while achieving narrow, pencil-like beams across multiple frequency bands. A fabricated prototype, measuring 80 mm × 80 mm, achieves peak gains of 20.2 dBi for the lower band and 22.7 dBi for the higher band, over a wide bandwidth of 23.5-29.2 GHz. Additionally, the antenna's peak gain frequency can be dynamically reconfigured by adjusting the feeder-radome distance, while its polarization can be controlled by rotating the feeder. These results show the antenna's great potential for millimeter wave communications and radar systems.