A bilayer array metamaterial based on silicon carbon foam/FeSiAl for broadband electromagnetic absorption

Abstract

In this paper, a bilayer array metamaterial (BAMM) based on silicon carbon (SiC) foam/FeSiAl composite was proposed and the electromagnetic (EM) absorption performance of the BAMM was enhanced by regulating the material composition and geometrical parameters. The introduction of magnetic FeSiAl particles contributed to the reinforced low-frequency absorption of the BAMM. The geometrical parameter design resulted in the broadened effective absorption bandwidth (EAB, reflection loss value≤−10 dB) by improving the impedance matching between the BAMM and the free space. At the same time, it was found that the tuning of the geometrical parameters has a more crucial effect on the absorption properties than the regulation of material composition. Moreover, the EM absorption mechanism was investigated by analyzing the distribution of the EM field and the power loss. In addition to the polarization and magnetic losses in the BAMM, the EM energy is mainly dissipated by the scattering effects concentrated at the outer edge of the unit cell and by the EM resonances between neighboring unit cells. The optimized SiC foam/FeSiAl-1based BAMM exhibits an effective absorption in the frequency range of 2–18 GHz by calculation, and then the corresponding experimental BAMM sample is prepared and measured. The experimental results are in good agreement with the simulations and demonstrate an EAB of 15.77 GHz, indicating that the geometrical parameters design based on high-loss materials is an attractive and efficient strategy to obtain broadband absorbers.