Microwave absorption properties of carbon fiber radar absorbing coatings prepared by water-based technologies

Carbon fiber radar absorbing coatings (CFRACs), composed of different amounts of carbon fiber (CF) embedded in polyurethane resin, were prepared using water-based technologies. The microstructures and properties of the coatings were characterized by means of scanning electron microscopy, differential scanning calorimetry, Fourier infrared spectrometry, X-ray diffraction analysis, and vector network analysis. Our results show that with an increase in CF content and thickness of coating, the peak reflection of the CFRAC moved in the low frequency direction. When the CF content was 0.8 wt% and the thickness of the coating was 1.2 mm, the maximum reflection losses of the coatings were -11.01 dB over the frequency range of 8-18 GHz, with a less than -10 dB (over 90% microwave absorption) bandwidth of nearly 4.2 GHz and a coating density of 1.02 kg m(-2). The results indicated that CFRACs could be a potential microwave absorbing material used over the frequency range of 8-18 GHz.