Triple-band polarization-independent terahertz absorber based on concentric slotted multimode structure

In this article, triple band polarization insensitive multiband metamaterial absorber is proposed for terahertz (THz) applications. The proposed unit cell size is of 140 × 140 µm 2 , consisting of a metallic radiator at the top layer with conducting ground plane of copper and polyamide substrate material with dielectric constant ε r = 4.3 and loss tangent tan δ = 0.004. Four concentric rings acting as resonators are designed to develop a triple band absorber. The proposed design is providing absorption at 0.615 THz, 0.951 THz and at 1.007 THz frequency with absorption of 97.5 %, 98.94 % and 99 % respectively. Due to symmetry in design, it is polarization insensitive from angles 0–60°. The results confirm that the proposed absorber design offers a wide range of THz applications in sensing, imaging and filtering.