Highly efficient meta-radiators with circular polarization

In this paper, circularly polarized metasurface radiators (meta-radiator) are elaborately designed with low-profile, small footprint, and highly efficient specifications. The proposed array consists of single-feed dense radiating meta-atoms that overall occupies a small area of 1.57 λ 0 × 1.57 λ 0 at f = 5.8 GHz. The inter-element coupling is involved by analyzing the contributing meta-atoms with Floquet boundary conditions. For demonstration purposes, an 8 × 8 sample of meta-radiators excited by an isolated network beneath the ground plane is fabricated. Both numerical and experimental results demonstrate that the meta-radiator exposes a pure left-hand circularly polarized radiation with a peak broadside directivity, a realized gain, and an axial ratio of 14.9 dBi, 14.2 dB, and 1.28 dB, respectively. Numerical simulations indicate that the aperture, radiation, and total efficiencies are as high as 99%, 97.5%, and 84.3%, respectively. In comparison with the conventional array antennas with similar performances, the proposed meta-radiator provides a higher aperture efficiency, in a simpler manner to achieve circular polarization, and more compact size as discussed throughout the paper. This new class of radiating architectures may find great potential applications in target detection systems and wireless communications.