Permittivity and Permeability of Mullite‐SiC‐Whisker and Spinel‐SiC‐Whisker Composites

Abstract

Real and imaginary permittivity (ɛ′ and ɛ″, 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 ɛ′ from 6.6‐6.9 to 16‐22 and increases ɛ′ from 0 to 16‐22. The addition of 32 vol% of SiCw to spinel increases ɛ′ from 7.5‐7.8 to 37‐44 and increases ɛ″ from 0 to 13‐20. The addition of 21 vol% of ZrO2 to mullite increases ɛ″ to ∼9 but does not change ɛ″. Real and imaginary permeability values were 1 and 0, which are within experimental error.