Efficient Beamforming Based on High-Transmittance Conformal Metasurface Fed by Slot-Coupled Patch Antenna Array.

We propose a beamforming method based on curved conformal metasurfaces fed by a slot-coupled patch antenna array. This conformal metasurface comprises five distinct planar metasurface subarrays and their corresponding feed array antennas, which are deployed on a cylindrical surface with a central angle of 60°. The feed array antenna, operating at 25 GHz, is designed based on the architecture of T-junction power dividers and slot-coupled patches, and this antenna is used as the feed for the metasurface subarray. The phase distribution of the transmission-type metasurface is computed based on the far-field synthesis expression of the cylindrical conformal array, resulting in main beams directed at elevation angles of 0, 15, and 30°. The radiation patterns of the conformal metasurface, as observed through experimental measurements, align well with the results derived from theoretical calculations, which confirms the efficacy of the beamforming methodology employed. This design effectively reduces the size of the feed, increases the spatial utilization of the conformal carrier, and broadens the applicability of the metasurfaces.