Microwave Dielectric Properties of ZnWO₄/Polypropylene Composites

Abstract

Effects of ZnWO₄ content and particle size on the dielectric properties of ZnWO₄/polypropylene(PP) composites were investigated at microwave frequencies. With increasing of ZnWO₄ content, the dielectric constant(K) of composites was increased, while the dielectric loss(tan δ) was slightly increased up to 0.3 volume fraction(V_f) and then decreased. For the composites with 0.1 V_f of ZnWO₄, K was decreased and tan δ was increased with the particle size of ZnWO₄. These results are due to the inter-particle distance and the degree of crystallinity. The temperature coefficient of resonant frequency(TCF) was also discussed for thermal stability of the composites.

Keywords:

• Composites
• Microwave dielectric properties
• Particle size
• Crystallinity

Acknowledgments

This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (2009-0078000).