Efficient asymmetric transmission for wide incidence angles using chiral split-ring-resonators

In this article, a chiral metasurface is proposed for controlling the linear polarization over broadband which consists of simple circular split-ring-resonator based unit cells on both sides of ultrathin (0.05λ at the operating frequency of 20 GHz) substrate. Across the large operating band (19.4–22.7 GHz), the structure is highly efficient with transmission efficiency greater than 0.94 and asymmetric transmission magnitude more than 0.8. Moreover, the structure exhibits stable response up to 45°, which is desirable for many K-band applications in radar and small satellite communication systems. The proposed metasurface acquires direction-dependent propagation with 90° linear polarization plane rotation, as depicted by simulated and experimental results. Furthermore, the structure is insensitive to circular polarized propagation within the operating band.