TiO2 tailored low loss NiCuZn ferrite ceramics having equivalent permeability and permittivity for miniaturized antenna

Abstract

Abstract Matching permeability and permittivity, low magnetic and dielectric loss tangent and high refractive index play a critical role in designing a miniaturized antenna with high performance. Here, TiO2 was introduced into Ni0.368Cu0.2Zn0.432Fe1.96O3.94 ferrite ceramic to adjust equivalent permeability and permittivity via suppressing grain growth. The effects of concentration of TiO2 and sintering temperature on microstructure, complex permeability and permittivity, DC resistivity, and saturation magnetization of NiCuZn ferrite ceramics were investigated. SEM results indicated that TiO2 obviously retarded grain growth to achieve uniform and dense NiCuZn ferrite ceramics with small grains (∼0.60 μm). Also, it was found that the addition of TiO2 can enhance the DC resistivity and reduce loss factors via increasing in fraction of grain boundaries. Furthermore, different sintering temperatures were chosen to control the matching permeability and permittivity and to promote densification. At last, a NiCuZn ferrite with the equivalent permeability to permittivity (μ′ = 12.90, e′ = 12.76, @ 40 MHz), very low loss factors (tanδμ = 0.050, tanδe = 0.00022, @ 40 MHz), and high DC resistivity was obtained sintered at 1000 °C when 16 wt% TiO2 was added. Thus, NiCuZn ferrite ceramics doping TiO2 show a lot of potential to be used as a substrate material in miniaturizing antenna for futuristic electronic devices.