Microwave dielectric properties of flexible silicone rubber – Ba(Zn1/3Ta2/3)O3 composite substrates

Silicone rubber composites filled with Ba(Zn1/3Ta2/3)O3 (BZT) were prepared by hot pressing and the effect of filler content on the microwave dielectric, mechanical and thermal properties as well as on moisture absorption were investigated. The observed relative permittivity (ɛr) was compared with different theoretical models. Among the different theoretical models Jayasundere Smith and Modified Lichtenecker were in good agreement with experimental values of ɛr. The study of the mechanical property showed that the silicone rubber – BZT composites were flexible and stretchable. The coefficient of thermal expansion and specific heat capacity decreased whereas thermal conductivity, thermal diffusivity and the moisture absorption increased with increase in filler loading.