Evaluation of the microwave absorption property of flake graphite

The effects of mechanical milling time, ultrasonic vibration time and the weight ratio of flake graphite in the absorber on the absorption property over the frequency range of 8-18 GHz were examined by the Radar Absorbing Material reflectivity far field Radar Cross Section method. A possible absorption mechanism was proposed for the enhancement of absorption ability with increasing milling time. Flake graphite exhibits good absorption performance in the high frequency. Specifically, the absorption peak value of flake graphite with milling time of 12 h is about 15 dB stronger than that of the unground flake graphite. The optimum weight ratio is 25% and the absorption ability of flake graphite (25%) from 14.4 to 18 GHz is >12 dB, which is the best of all the samples.