Realizing efficient asymmetric transmission using optical activity of ultrathin chiral metasurfaces for K-band applications

An elliptical chiral split-ring-resonator-based bilayer thin metasurface is introduced in this paper. The proposed metasurface realizes strong electromagnetic (EM) activity with asymmetric transmission in the K-band of the microwave regime. The efficiency is more than 80% over a range of frequencies from 18.6 to 20.8 GHz. Angular stability up to 60 degrees makes the structure robust for practical applications. The structure also exhibits a negative refractive index for circularly polarized wave due to the strong chirality factor. Polarization azimuth rotation angle of 90 degrees and ellipticity of 0 degrees reveal the pure EM/optical activity. Furthermore, the simulation and measured results also affirmed orthogonal pure linear polarization transformation. The proposed chiral metasurface finds applications in radar and satellite belonging to K-band.