Two phase Mg0.7Cd0.3Fe2O4–BaTiO3 composite ceramics with excellent magneto-dielectric properties for antennas in GHz band

Two phase-based composites comprising barium titanate (BaTiO 3 ) and spinel magnesium ferrite (1- x )Mg 0.7 Cd 0.3 Fe 2 O 4 + x BaTiO 3 (x = 0.00, 0.03, 0.06, 0.09, and 0.12) were investigated. The phase structure revealed the coexistence of the perovskite BaTiO 3 and spinel MgFe 2 O 4 phases. The microstructural analysis indicated that the average crystallite size initially increased and then decreased, as the increase in x weakened magnetisation, decreased saturation magnetisation (from 47.5 to 35.9 emu/g) and coercivity (150–0 Oe) were obtained, resulting in reduced permeability at low frequency. The permittivity gradually increased owing to tuning by barium titanate, which has strong dielectric properties , promising a relatively large miniaturisation factor. Further, low magnetic loss (tan δ μ ∼10 −2 ) and dielectric loss (tan δ ε  ∼ 10 −2 to 10 −3 ) guarantee high quality factor. The low losses and enhanced dielectric properties of the as-synthesised composites could be conducive to improving the behaviour of such magneto-dielectric composite systems in microwave applications.