The study of geometries effect of hexagonal metamaterial absorber in the terahertz regime

Metamaterials (MMs) are the artificially engineered materials that can exhibit particular electromagnetic properties such as negative refractive index, left-handed behavior, extraordinary transmission, etc. These fascinating properties of MMs are of great and increasing interest to be used in various applications in the terahertz regime (0.1-10 THz). In this study, the electromagnetic property of metamaterial that we are interested is an extraordinary transmission for creating a "Metamaterial Absorber (MMA)". Over the past decade, there has been a number of designed patterns of metamaterial absorbers having high absorptivity and also multi-absorption characteristics such as split-ring resonator, square, U-shape, T-shape and Hexagon. Most of the Hexagons are designed to have the absorption characteristics in GHz frequency. We intend to investigate the effects of the parameters regarding the absorption in the terahertz regime, especially in 0.3-5.0 THz for various applications such as security and medicine. The proposed absorber structure in this study consists of 3 layers which are a periodically arranged metallic hexagonal pattern layer, a dielectric layer, and a continuous metallic layer. Length, width, number of gaps, gap size, the position of a gap of the hexagon in the first layer are the studied parameters. The proposed hexagon metamaterial absorber of the first design having 5 gaps with gap size 5 μm each located at the corner of the hexagon provide 4 absorption bands with high absorptivity. For the other design having 6 gaps with gap size of 5 μm each located at hexagon side show not only 3 narrow bands of perfect absorption but also a broadband absorbance for the terahertz regime around 3 THz.