Abstract
In this paper we investigate microstructure and electrical properties of NiZn ferrite ring cores and influence of different temperatures on these properties in the wide frequency range from 10 kHz to 1 GHz. Important electrical parameters are analyzed through measuring inductance, impedance and phase angle using LCZ meter HP4277A for lower frequency range (10 kHz–1 MHz) and RF Impedance analyzer HP4191A for higher frequencies (1 MHz–1 GHz). The complex permeability spectra of two ferrite materials, labeled with F14 and F19, has been calculated by means of these measured parameters. It can be concluded that, up to a certain frequency, permeability increases with temperature increase and above that frequency this behavior is opposite. The normalized temperature characteristics of permeability and impedance are also given for analyzed samples.