Greatly enhanced magneto-dielectric performance of the Ni_(0.5)Zn_(0.5)Fe_2O_4/polyvinylidene fluoride composites with annealed ferrite powders for antenna applications

摘要

A series of Ni_(0.5)Zn_(0.5)Fe_2O_4 (NZO)/polyvinylidene fluoride (PVDF) composites were prepared and studied for their potential application as magneto-dielectric antenna substrate materials. The NZO ferrite powders were synthesized by the solid-state reaction method and then annealed at different temperatures of 700, 900 and 1100 ℃. The influence of the annealing treatment on the grain size, crystallinity and magneto-dielectric properties were discussed. The magnetic and dielectric properties of the composites were measured in 1 MHz-1 GHz and 100 Hz-1 GHz, respectively. With the annealing temperature increase from 700 to 1100 ℃, the initial permeability of the composites increases from 3.89 to 7.93, while the static permittivity changed regularly with the growing grain size. Almost equal values of μ′ and ε′ are obtained in the composite sample with the 1100 ℃ annealed NZO powders. Considering the relatively low magnetic and dielectric loss tangent, this material is the promising candidate for the design of miniaturized antennas.