Simple structure THz metamaterial with broadband double-negative refraction

Abstract

A broadband negative-refractive index metamaterial, composited of two square-shaped aluminum apertures with different title angles etched on both sides of polyimide substrate, has been proposed. The calculated results indicate that the coupling between the titled and untitled square-shaped apertures is more conducive to the high-pass and broadband transmission than the combination of two untitled structure. The high-pass band of metamaterial increases from 0.43 to 0.76 THz with the increasing aperture width from 30.0 to 35.0 μm, meanwhile, the maximum bandwidths of double-negative refraction and negative-refractive index can reach up to 0.58 and 0.78 THz, respectively. The highpass transmission mainly locates at the double-negative refraction region. Furthermore, the negative refraction of the NIMs has been verified by the classical method of the wedge, and the results show many unique properties of the symmetric slab waveguide based on the proposed NIM.