Angularly stable asymmetric transmission for K-band applications through optical activity of a chiral Metasurface

• A novel bi-anisotropic chiral metasurface for optical rotation with asymmetric transmission. • Acheiving x- to y- and y- to x- polarization conversion efficiencies of upto 90 % for a large bandwidth covering 19.2–22.2 GHz. • Asymmetric transmission of linear polarized waves is also achieved with asymmetric parameter above 85 %. • Angular stability of up to 60° in forward direction and up to 45° in backward direction for oblique incidence. • Analysis of effective medium parameters like refractive index, impedance, permittivity, and permeability. A novel bi-anisotropic chiral metasurface for optical rotation with asymmetric transmission is proposed and analyzed in this research work along with experimental verification of the results. The proposed metasurface consists of simple chiral heptagon-shaped Split Ring Resonators (SRR) with elongated arms, on both sides of an ultrathin substrate of thickness 0.053 λ o . Numerical and measured results show that x- to y- and y- to x- polarization conversion efficiencies of the metasurface in forward and backward wave propagation, respectively, are above 90 % for a large bandwidth covering 19.2-22.2 GHz. Asymmetric transmission of linear polarized waves is also achieved with asymmetric parameter above 85 % across the entire operating frequency band. The metasurface gives an angular stability response up to 60° in forward direction and up to 45° in backward direction for oblique incidence. The effective medium parameters like refractive index, impedance, permittivity, and permeability are also retrieved for the proposed metasurface. Due to the abilities of polarization control and diode like efficient linear asymmetric transmission, the proposed design is practically suitable for radars and satellite applications in K-band.