Influential parameters on electromagnetic properties of nickel–zinc ferrites for antenna miniaturization

Abstract

Electromagnetic properties of nickel-zinc ferrites based materials make them potential candidates for applications linked to telecommunications. In the present study, nanosized particles of spinel ferrite Ni 0.5 Zn 0.3 Co 0.2 Fe 2 O 4 were prepared by coprecipitation method. An optimized material is obtained after adequate heat treatment and partial filling of the porosity by epoxy resin. This material lies between ceramic and composite medium ͑with porosity close to 40%͒, and shows almost constant complex permeability and permittivity in the frequency range from 0.1-0.7 GHz, and equal to ϳ3.5-j0.15 ͑loss tangentϳ 0.04͒ and ϳ4-j0.2 ͑loss tangentϳ 0.02͒, respectively. The refractive index n is close to 3.75. These electromagnetic properties, in particular the low levels of losses, show that this material could be useful to the design of miniaturized antennas in the VHF-uhf ͑300-700 MHz͒ range of frequency.

Pressure Dependence of the Frequency Permeability Spectra of Soft Ferrite Composite Materials: A Method of Measuring the Natural Ferromagnetic Resonance Frequency

“…Straightforward calculations on [111] axe (the studied materials present four easy axes) leads to (1) The ferrimagnetic resonance frequency is given by where is the gyromagnetic ratio ( ), that is…”

“…More details on synthesis process and on structural characterization can be found in [1]. Soft magnetic composite materials were prepared by mixing epoxy resin with ferrite particles (with a magnetic load C at about 0.5).…”

Experimental determination of magnetocrystalline anisotropy constants and saturation magnetostriction constants of NiZn and NiZnCo ferrites intended to be used for antennas miniaturization

“…Hence, domain-wall contribution leads to high permeability values, but magnetic losses associated with domain-wall bulging remain high from the quasi-static frequencies until several 100 MHz. With the aim of avoiding these low frequency losses, our team first suggested using porous (i.e., halfmassive) ferrite ceramic in a bulk form, in which the grain size is small enough [21]. The magnetic phase of this porous nanostructured material is constituted by nanograins of ferrite.…”

Structural and microwave characterization of Ni0.2CoxZn0.8−xFe2O4 for antenna applications

“…Ferrites with low loss tangents (both dielectric and magnetic) are very useful to the design of miniaturized antenna and also for maintaining the electrical dimensions (the electrical length is the product of the geometrical length of the medium and its refractive index) [6]. The performance of porous ferrite materials in their bulk form where the grain size is big leads to high magnetic loss [7].…”