Multifrequency Radiator With Spatial Diversity Based on Metasurfaces

A low-profile multifrequency antenna that radiates at a different half-space at each of its frequency bands has been designed, numerically evaluated, fabricated, and tested. The antenna consists of a U-slot dipole placed between two metasurfaces composed of grids of cut and continuous wires. The fabricated prototype radiates toward the upper half-space at the low-frequency band with 6.1 dBi gain (10 dB of front-to-back radiation ratio) and toward the lower half-space at the high-frequency band, with two peaks of 7.6 and 6.8 dBi gain (with 12.6 and 23.8 dB front-to-back radiation ratio, respectively). The antenna remains planar with a thickness of 0.15 at 9.3 GHz.