An ultra-wideband metamaterial absorber with active frequency selective surface

We present an ultra-wideband metamaterial absorber with active frequency selective surface (AFSS). The metamaterial absorber consists of a periodic arrangement of AFSS patterns and a metallic back-plane, separated by 4 mm dielectric spacer. By adjusting the bias voltage of the PIN diodes embedded in the AFSS cells, we achieve three absorbing bands at different frequencies. Finite element method (FEM) simulation is carried out to discuss the absorbing properties of the absorber. The experimental results demonstrate that the metamaterial absorber has wideband absorption with a reflectivity below -8 dB over the microwave range from 2.43 to 14 GHz.