Mechanism research of extending absorption bandwidth of magnetic composite by loading metal periodic array

摘要

Spherical carbonyl iron-polyurethane composite absorbers with volume fractions of 20% and 50% were prepared. By placing the absorber with 50% volume fractions in the bottom and the absorber with 20% volume fractions in the top, the double-layer magnetic absorber was obtained. The absorption intensity of less than -10 dB covers 5.1-9.9 GHz. By loading a metal periodic array in the middle of the double-layer absorber, the absorption band was extended to 13.4 GHz. To investigate the underlying mechanism of the absorbing performance improvement, based on the interference theory, the symmetry model was applied to separate the waves reflected at different interfaces of the absorber. The energy loss from interference cancellation and energy attenuation in the medium were quantitatively examined. By analyzing the change of the separated reflected waves before and after loading the array, the interference loss was proved enhanced, which results in optimized the absorption performance and the broadening of the bandwidth.