Low-loss NiCuZn ferrite with matching permeability and permittivity by two-step sintering process

Abstract

Magneto-dielectric materials with matched permeability and permittivity are promising candidates as loading materials to reduce the physical dimensions of low-frequency antennas. In this study, NiCuZn ferrites were prepared by both the traditional final-stage sintering process and the two-step sintering process to obtain the magneto-dielectric materials. It was found that the samples sintered by the two-step sintering process tended to obtain microstructure with dense, homogeneous, and small average grain size, which was favorable to obtain low magnetic and dielectric losses. The sample sintered by the two-step sintering process with high temperature 950 °C and holding temperature 900 °C could obtain almost equal permeability and permittivity of around 11.8. And the magnetic and dielectric loss tangents were lower than 0.015 in a frequency range from 10 to 100 MHz. These properties make the material useful to the design of miniaturized antennas.