根据阻抗匹配原理和电磁波传播规律,以中空多孔聚丙烯腈(PAN)碳纤维为主要吸收剂,分别添加以炭黑、碳纤维和羰基铁粉为吸收剂的匹配层,制备了双层轻质雷达吸波材料,并考察了其吸波性能.结果表明,双层结构设计和不同吸收剂的复合对提高材料的吸波性能起着重要的作用.以羰基铁粉作吸收剂的匹配层比以炭黑和碳纤维作吸收剂的匹配层对提高以中空多孔碳纤维吸波材料的吸波性能更为显著.所制备的材料在厚度为2.90mm,密度为1.28g/cm^3时,在4-18GHz频率范围内反射率≤-8dB的带宽为11.42GHz,反射率≤-10dB的带宽为10.90GHz.
A kind of lightweight and wideband radar absorbing materials were prepared based on resistance matching principles and electromagnetic wave propagation laws. These materials consist of two-layers, one made of PAN-derived hollow-porous carbon fibers contributing to the low density, and the other made of car- bon blacks, short carbon fibers or carbonyl iron powders acting as the matching layer. Their radar absorbing properties investigated show that the introduction of the matching layer, as well as the properties of the matching layer, plays an important role in improving the absorbing properties of the materials. Carbonyl iron pow- ders are more suitable for the matching layer than the other two as the radar absorbing properties concerned. Thus obtained material has a bandwidth of 11. 42GHz under -8dB, and a bandwidth of 10. 90GHz under - 10dB in the range of 4 - 18GHz, provided that the thickness and the density are 2.90mm and 1.28g/cm^3, respectively.