Low-loss spinel nanoferrite with matching permeability and permittivity in the ultrahigh frequency range

摘要

Ferrite nanoparticles with a composition of Ni0.5Zn0.3Co0.2Fe2O4 were prepared by a coprecipitation method. The sample obtained after treating at appropriating conditions had almost equal real permeability and permittivity, of 4.8+j0.15 (loss tangent∼0.04) and 4.9+j0.10 (loss tangent∼0.018), respectively, over 100 to 500 MHz. This material had a refractive index n of close to 5 and a reduced impedance Z/Z0 of close to 1. These properties make the material useful to the design of miniaturized antennas at very high frequency-ultra high frequency (VHF-UHF) (100–500 MHz) bands.