Abstract: On the basis of the complex effect and design principle of structural composites, applying activated carbon fiber felts screen/epoxy (ACFFS/EP) as wave-absorption layers, carbon fibers (CF) as enhanced wave-absorption agents and glass fiber (GF) as impedance matching layer respectively, GF/CF/ACFSS was prepared by layer-by-layer assembly technique with the help of tailor-made mold. The effect of chopped CF mass fraction and of arrangements between the layers on microwave absorbing performance of GF/CF/ACFFS was investigated. Experimental results show that the maximum reflection loss(RL) to electromagnetic wave was up to -38.54 dB at the frequency of 14.2 GHz for three-layers GF/CF/ACFFS composites with ACFFS/EP at bottom when the mass fraction of CF is 0.7% within the frequency range of 2~18 GHz. In addition, the effective absorbing bandwidth (RL<-10 dB) was acquired at 11.33 GHz (6.17~17.5 GHz). Optimum microwave absorbing property of composites can be acquired with the suitable mass fraction of chopped CF, and absorbing materials with excellent property will be obtained when keeping reasonable combination of CF and ACFFS.

Key words: ACFFS, chopped carbon fiber, reflection loss, absorption bandwidth