Optimization of Ni0.95−xZnxCo0.05Fe1.90Mn0.02O4 ceramics with promising magneto-dielectric properties for VHF antenna miniaturization

Abstract

Magnetic, dielectric and DC conductive properties of Ni0.95−xZnxCo0.05Fe1.90Mn0.02O4 (with x=0-0.20 at an interval of 0.05) ferrite ceramics were studied, in order to develop magneto-dielectric materials with almost equal values of relative permeability and permittivity, for the miniaturization of HF (3–30MHz) and VHF (30–90MHz and 100–300MHz) antennas. The ferrite ceramics were prepared by using the conventional two-step sintering process. The real part of relative permeability is increased almost linearly with increasing concentration of Zn, while that of relative permittivity keeps nearly unchanged. It is found that promising magneto-dielectric materials, with close values of real permeability and permittivity over 30–90 MHz (VHF), can be obtained for the samples at Zn concentrations between x=0.05 and x=0.10.