Wideband circularly polarized slot antenna over meta-surface

A wideband, unidirectional, metasurface backed slot antenna is proposed and studied for the circularly polarized radiation. Proposed antenna consists of a wide octagonal-shaped slot backed by metasurface. Conventional L-shaped stub feed with an impedance transformer is used to excite the octagonal-shaped slot radiator. The measured results of the antenna prototype are 40.2% (4.70-7.11 GHz) for 3-dB axial ratio bandwidth, 41.7% (4.95-7.45 GHz) for 10-dB return loss bandwidth, and around 6.0 dBic for the gain at the boresight. The antenna exhibits an overall volume of 0.72λ_o × 0.60λ_o × 0.28λ_o at 6.0 GHz.