Abstract:
A metamaterial absorber based on fractal structure is designed in terahertz regime. Dual-band absorptions are presented. The influence of substrate thickness on absorptivity is investigated through numerical simulation. With regulation of substrate thickness, impedance matching between the absorber and free space is approximately achieved. When substrate thickness is 5.4 μm, the reflectivity of the first resonant point A is low, but the absorptivity is high. When substrate thickness is 1.4 μm, the absorptivity of the second resonant point B reach 99.9%. With the increase of fractal dimension, point B moves to high frequency, but its absorptivity remains. Simulation results show that the absorbers with different resonant frequencies can be designed by adjusting the fractal dimension. With simulation and optimization of double-layer and triple-layer structures, the broadband absorbers are also designed.
