Enhanced asymmetric transmission due to Fabry-Perot-like cavity.

In this paper, a three layered metamaterial composed of a ring-chain structure sandwiched between two layers of twisted sub-wavelength cut-wire arrays is proposed and investigated. The designed structure is optimized such that asymmetric transmission with an extremely broad bandwidth, sharp rejection stop-band and high transmittance is achieved. The physical mechanism is accounted for that the metallic layers form the Fabry-Perot-like resonance cavity, enhancing the polarization conversion efficiency between two orthogonal linearly polarized waves. To some extent, this approach offers a way to strengthen asymmetric transmission effect.