Dielectric properties of SiC fiber-reinforced SiC matrix composites in the temperature range from 25 to 700 °C at frequencies between 8.2 and 18 GHz

The complex permittivity of a SiC fiber-reinforced SiC matrix (SiCf/SiC) composite was measured in a temperature range of 25–700 °C at frequencies from 8.2 to 18 GHz. The SiCf/SiC composite exhibited a positive temperature coefficient, that is, its complex permittivity increased with temperature. The observed positive temperature coefficient can be interpreted by Debye theory, by which the theoretical predictions were in well agreement with the experimental results.