A metamaterial absorber with mortise structure for improving the terahertz wave absorption

Metamaterial absorbers have been reported for excellent absorption in terahertz. Based on the traditional metamaterial structure, we proposed a new design method for metamaterial absorber by introducing mortise structure. Simulations results demonstrated that the metamaterial absorbers can significantly increase the absorption and broaden the absorption bandwidth. The effective absorption bandwidth is increased from 0 THz and 0.58 THz to 1.52 THz and 1.58 THz in two selected example metamaterial absorbers. The absorption increased by 19 % and 4 %, respectively. And the maximum absorption is close to perfect absorption. Then a terahertz wideband metamaterial absorber is designed based on this structure by changing the number of corners in the cell pattern. The thickness is only 8.2 mu m, the terahertz absorption exceeds 90 % in 4.5-7.1 THz. The metamaterial absorber has the characteristics of polarization insensitive and wide angle, which provides a new design method for the development of terahertz absorbers.