Abstract: Carbon nanotube-fused silica composite powders were synthesized by a sol-gel method, and then the composite powders were hot-pressed to obtain relatively dense composites. Complex permittivity spectra of these composites were obtained at 8--12GHz. The experimental results show that the complex permittivity increases as the volume content of carbon nanotube increases in the measured frequency region. High imaginary permittivity reveals that these composites exhibit considerable dielectric loss. Refection loss of these composites calculated with transmission-line theory shows that these composites have obvious electromagnetic wave absorption ability and the reflection loss is sensitively relative to the thickness of composites and the volume content of carbon nanotube. The absorption properties of the composites are also improved by designing two-layer carbon nanotube-fused silica composites.

Key words: carbon nanotube, composites, electromagnetic wave absorption properties, design