Asymmetric Transmission Of Linearly Polarized Electromagnetic Wave Through Chiral Metamaterial Structure

Abstract

In this paper, we propose a chiral metamaterial structure that enables asymmetric transmission of linearly polarized electromagnetic (EM) wave. The metamaterial is composed of twisted metallic split-ring resonator structures on both sides of a dielectric substrate. By full-wave EM simulations and free space measurements, a strong asymmetric transmission of linearly polarized EM wave, through such a thin metamaterial slab, has been demonstrated in the microwave band. It allows propagation of linearly polarized EM wave in one direction, while almost no propagation is in the opposite direction. Strong optical activity has also been found indicating that the metamaterial slab with a thickness of one-fifteenth the operational wavelength could rotate the linear polarization of the incident wave to its orthogonal polarization. The proposed chiral metamaterial structure could be useful in designing novel nonreciprocal EM devices, as well as polarization control devices.