Permittivity and permeability of mullite-SiC-whisker and spinel-SiC-whisker composites

Real and imaginary permittivity (epsilon' and epsilon", respectively) values were determined on mullite-silicon carbide whisker (mullite-SiCw) composites, mullite-ZrO2 composites, and spinel-SiCw composites, in the frequency range of 2-18 GHz, using a 14 mm coaxial air-line measurement system. Depending on the frequency, the addition of 30 vol% of SiCw to mullite increases epsilon' from 6.6-6.9 to 16-22 and increases epsilon' from 0 to 16-22. The addition of 32 vol% of SiCw to spinel increases epsilon' from 7.5-7.8 to 37-44 and increases epsilon" from 0 to 13-20. The addition of 21 vol% of ZrO2, to mullite increases epsilon" to similar to 9 but does not change epsilon". Real and imaginary permeability values were 1 and 0, which are within experimental error.