Influence of ground plane with variable conductivity on metamaterial absorption

Most researches of metamaterial absorber (MA) focused on varying the resonator and dielectric spacer to configure the absorption and resonant frequency, and the ground plane was generally considered as a perfect reflector. In this paper, we developed a method to tailor the MAs absorption by varying the conductivity of the ground plane. Our quantitative analysis reveals that with the decrease of the conductivity from 4.1 × 10⁷S/m to 3.0 × 10⁵S/m, the absorptivity of the electric resonance decrease by 27%, while that of the dipole resonance increase by 85%. The theoretical calculations are in excellent agreement with the simulations and experiments. A 44% increase of the absorption was experimentally obtained at dipole resonance. Our approach provides not only a technique to tailor absorption, as well as a practical method to measure the electric conductivity of the metallic film at terahertz regime.