Research on Multiple-Band Terahertz Metamaterial Absorbers Having Narrow Discrete Spacing Enabled by Multiple Parallel Metallic Strip Resonators

A dual-band terahertz metamaterial absorber having narrow discrete spacing is presented in this work. The basic cell of the dual-band absorption comprises two parallel metallic strips and metallic backplane separated by an insulating dielectric layer. Two near-perfect absorption peaks with narrow discrete spacing of 0.24 THz are obtained, and their relative discrete spacing is 10.62%. Importantly, its discrete spacing or relative discrete spacing can be narrowed by choosing appropriate structure parameters. Results demonstrated that the discrete spacing of only 0.1 THz (or relative discrete spacing of 4.57%) is obtained by adjusting the length of one of the metallic strips. Moreover, narrow discrete spacing of a triple-band terahertz metamaterial absorber formed by three parallel metallic strips and an insulating dielectric layer placed on the metallic plate is further designed. The triple-band absorption device possesses two narrow discrete spacing, which are respectively 0.24 THz and 0.22 THz with the relative discrete spacing of 10.39% and 10.05%, respectively. Results further revealed that the triple-band absorber also has the possibility of narrowing the discrete spacing by employing different lengths of metallic strips. These proposed multiple-band absorption devices with narrow discrete spacing could have considerable application potential in many technology-related fields.