Design of four-band terahertz perfect absorber based on a simple #-shaped metamaterial resonator

We propose a simple and novel design of four-band terahertz perfect metamaterial absorber composed of a periodic arrangement of metallic #-shaped strip and a metallic background plane, separated by a dielectric polyimide spacer. Theoretical results show that the proposed absorber has four distinct absorption bands whose peaks are average over 99 %. Different from previous reports by combining the resonances of the complex structure (coplanar super-unit structure or stacked multilayer structure) to realize multiband response, the proposed structure primarily utilizes the combination of LC and electric dipole resonances of the single patterned structure, thus making the proposed structure very easy to be fabricated. Furthermore, sensing performance of the absorber is analyzed in terms of the over-layer and the surrounding index.