Ultra-wideband and polarization-insensitive fractal perfect metamaterial absorber based on a three-dimensional fractal tree microstructure with multi-modes

摘要

In this paper, an attractive, ultra-wideband, and polarization-insensitive fractal perfect metamaterial absorber had been proposed based on a tree-shaped microstructure. The absorber was composed of two dielectric substrates, a three-dimensional fractal metal tree, and four lumped resistances. The absorption mechanism and different modes for the absorber had been analyzed in simulation. The characters of polarized-insensitivity and wide-incident absorption for the proposed metamaterial absorber were systematically illuminated by the near electric fields, angular absorptions, and surface current distributions. A presented perfect metamaterial absorber device had been easily implemented using the common printed circuit board method and was measured in a microwave anechoic chamber. The results showed that this proposed FPMA provided a relative bandwidth of 86.9% with the absorptivity larger than 80%. Both the simulated and experimental results adequately verified the characters of wideband, wide-incident, and polarization-insensitive absorption.