Microwave absorbing properties of active carbon－fiber felt screens( vertical2arranged carbon f ibers) / epoxy resin composites

Microwave absorbing properties of the composites containing active carbon-fiber felt screens (ACFFSs)or vertical-arranged carbon fibers (VACFs) were investigated respectively. The results show that the absorbing performances of the composites containing ACFFSs are affected greatly by the patterns (inductive or capacitive) and theelement configurations of ACFFSs. The composite containing the inductive screen obtains a reflection loss below- 10 dB at 8～18 GHz , which is the frequency region of the radar , when the distance between st rip s and the widthof st rip s are 7 mm and 5 mm respectively. The absorption effect of the composites rises with reducing the side ofplates or the distance between plates in the capacitive screen. The space between fibers is critical for the absorbingperformances of the composites containing VACFs. The bandwidth below - 10 dB is 7. 6 GHz when the space is 4mm. By applying the block design method , the composite was divided into four sub-regions which were cent rosymmet rical and contained two inductive screens and two VACF regions. The composite achieves a reflection loss below- 20 dB at 11. 8～18 GHz and the minimum value reaches - 30 dB when the distance between st rip s , the width ofst rips and the space between fibers are 10 mm , 5 mm and 8 mm separately.