Influence of thermal oxidation on complex permittivity and microwave absorbing potential of KD-I SiC fiber fabrics

The complex permittivity and microwave absorbing potential of KD-I SiC fiber fabrics at X band as functions of thermal oxidation time and temperature were investigated. The values of ε′ (real part) and ε″ (imaginary part) of the complex permittivity of the fabrics decreased with increasing thermal oxidation time and temperature. It was found that the microwave absorbing potential of fabrics can be optimized by thermal oxidation. The best reflection loss was obtained for the sample oxidized for 30 min at 500°C. Its lowest reflection loss is about-25. 4 dB at 10. 3 GHz, and its absorbing frequency band is about 4 GHz. The oxidized KD-I SiC fiber fabric is a good microwave absorbing material with low density, high temperature resistance, and flexibility.