Magneto-Dielectric Characterization of (Zn2Y)0.4(NiF)0.6 Composite for High Frequency Antenna Application

Abstract

There has been an explosion of interest in the research of composite ferrites for many exciting applications [1]. Hexagonal ferrite and spinel ferrite composites have been reported to show the tuning of magneto-dielectric properties and proposed for high-frequency application [1, 2]. The Ytype hexagonal ferrite; Ba2Zn2Fe12O22 (Zn2Y) and NiFe2O4 (NiF) spinel ferrite composite; (Zn2Y)0.4 (NiF)0.6 was prepared by one step co-precipitation route and solid state mixing route. Precursor powders were calcined at different temperatures in the range 400 to 1000oC to study the phase formation behaviour. Pellets and toroids were fabricated using calcined powder and sintered at 1220oC. Phase composition was evaluated by Rietveld analysis of XRD pattern (Fig.1(A)). The FESEM microstructure of sintered specimen (inset of Fig 1(A)) shows development of plate like Zn2Y ferrite grains and cubic NiF spinel ferrite grains together. Permittivity (εr) about 17, permeability (μr) of about 20, dielectric loss (tan ) of ~0.14, magnetic loss (tan µ) of ~0.17 were found at 200 MHz frequency. Miniaturization factor of 17.63 and characteristic impedance of 1.09 were evaluated at 200 MHz. Magnetodielectric resonator antenna was simulated based on dielectric and magnetic properties using ANSYS HFSS. Return loss (S (1,1 ~ -37 and voltage standing wave ratio of ~1.4 were derived from simulated results (Fig.1(B)).