Research on millimeter wave extinction of carbon fiber and its modified materials

Carbon fiber is an excellent functional and structural material with combining a variety of properties. In order to combat photoelectronic reconnaissance and guidance weapons, carbon fiber is widely used in the military field as interference millimeter wave smoke agent, and has become a hot issue in smoke screen passive interference technology. In order to explore the millimeter wave attenuation performance of carbon fiber and compare the interference effect of carbon fiber powder and short-cut carbon fiber on millimeter wave, experiments have measured the attenuation performance of carbon fiber powder with particle sizes of 25, 35, 70, 140, 200, 400, 800 and chopped carbon fiber to 3 millimeter waves and 8 millimeter waves. The research results show that chopped carbon fiber has a strong interference effect on millimeter waves. Short-cut carbon fibers with lengths of 1.5mm and 4mm are most effective at attenuation of 3mm waves and 8mm waves. In order to improve the millimeter wave attenuation performance of chopped carbon fiber, the carbon fiber is modified by electroless cobalt plating. It is found that the modified chopped carbon fiber has better millimeter wave attenuation performance than simple chopped carbon fiber, and it is closely related to the thickness of the coating. Compared with the attenuation ability of carbon fiber before modification, under the condition of optimal loading (optimum weight gain rate), after electroless cobalt plating, the attenuation rate of 3mm wave increased by 11.5%, and the attenuation rate of 8mm wave increased by 10.37%.