Microwave Absorbing Properties of Short Hollow Carbon Fiber Composites
短切中空多孔碳纤维复合材料的吸波性能

In order to get lightweight radar wave absorbers, hollow carbon fibers were prepared from polyacrylonitrile (PAN) hollow fibers by thermo-oxidative stabilization in air and carbonization in nitrogen. The microstructure and microwave absorbing properties of the resultant PAN-based hollow carbon fibers (PAN-HCFs) were studied by SEM, XRD and voter network analyzer. The reflectivity was simulated by using RAMCAD software. Results show that the electromagnetic parameters of the absorbing materials increase with increase of the PAN-HCFs volume fraction. The reflection coefficient apex moves to lower frequencies with the thickness of absorbing material increasing. With increase of volume fraction of the PAN-HCFs, the reflection coefficients increase greatly and the optimal thickness decreases at the same time. It is found that the 2mm thick composites containing 33.30% PAN-HCFs has an absorbing bandwidth of 5.17GHz below -5dB and 2.88GHz below -10dB in the frequency range of 2-18GHz.The lowest reflection is -21.36dB at 10GHz. The PAN-HCFs are proved to be a light conductive radar absorbing materials in view of its hollow structures and microwave absorption properties.