Low-profile wideband dual-circularly polarized orbital angular momentum antenna array using metasurface

A novel wideband dual-circularly polarized orbital angular momentum (OAM) antenna array using metasurface is proposed. The proposed antenna array composed of four antenna elements generates OAM beams in a simple configuration. Each antenna element is placed perpendicularly to the adjacent one, and fed by an in-phase excitation with equal amplitude. Each antenna element is based on corner-truncated polarization-rotation metasurface (PRMS) cells and excited by a dual-feeding structure through a cross-like slot, which can realize wideband dual circular polarization (RHCP, LHCP). The proposed antenna array produces dual-mode OAM mode waves (l = +/- 1) and exhibits good dual-circularly polarized performances in a low profile of 0.068 lambda(0). The measured results show wide impedance bandwidths of 30% for LHCP and 26.6% for RGCP. Also, the large axial ratio bandwidths ARBWs of the OAM antenna array are 20% for LHCP and 14% for RHCP.