Multiband THz Metamaterial Absorber Based on Snowflake-type Resonators

Recently, the devices operating in the terahertz (THz) frequency band have aroused tremendous interests because of their gigantic potential applications in the areas such as security, public health, and biomedicine. In this work, ultrathin multiband THz metamaterial absorbers are proposed, and the design, simulation, and theoretical analysis of the absorbers are presented. First, a dualband absorber consisting of snowflake-type resonator array is designed, which is printed on a grounded polyimide dielectric spacer. Numerical simulations shows that the proposed structure has two perfect absorption peaks at 0.952 and 1.818 THz with absorption rates reaching 99.7% and 99.9%, respectively. By carefully designing the geometrical parameters and layout of the snowflake-type resonators, a quadband absorber with four perfect absorption peaks is implemented. The numerical simulation result shows that four different absorption peaks appear at 0.752, 0.950, 1.454, and 1.696 THz with the absorption rates of 98.8%, 97.8%, 92.1%, and 90%, respectively.