A second-order cross fractal meta-material structure used in low-frequency microwave absorbing materials

A second-order cross fractal meta-material structure was designed and fabricated in this project. A kind of conventional magnetic material which works at low frequency was used as the absorber substrate. The simulation results demonstrated an absorber band below ?10 dB between 4 and 8 GHz, and there was a 1.7 GHz expansion when the meta-material structure was not loaded. The experiment results indicated a similar absorber band between 3 and 5.5 GHz, which was 1.09 GHz wider than meta-material structure and the absorber band expanded by 88 %. Then we further analyzed the energy distribution on the surface of the meta-material structure which perfectly explained the expansion of the absorption band and implied a way to achieve a lower wider absorber band.