Highly oriented flake carbonyl iron/carbon fiber composite as thin-thickness and wide-bandwidth microwave absorber

Oriented flake carbonyl iron/carbon fibers (FCI/CF) composite with enhanced microwave absorption properties were prepared. The effects of orientation, the addition of CF, and the orientation direction of CF on the microwave absorption properties were investigated, respectively. Compared with the un-oriented FCI composites, higher permeability was obtained due to the FCI orientation. Anisotropic electrical properties of FCI/CF composite were achieved by changing the arranged orientation of CF. A novel double-layer microwave absorber by combining FCI/CF absorbers with different orientation of CF was designed to achieve absorbers with wide absorption band and optimal microwave absorption. The calculated absorption properties indicated that wider absorption bandwidth and thinner thickness were obtained by the single-layer oriented composites, and the absorption properties were further enhanced by the double-layer composites. The double-layer FCI/CF composites show a wider absorption frequency range of 12.0 GHz from 6 to 18 GHz with reflection loss (RL) below −5 dB at thickness of 0.8 mm.