A Practical Method to Define High Frequency Electrical Properties of MnZn Ferrites

Ferrites are the choice magnetic materials for high-frequency and high power-applications. However, the typical material specification does not provide sufficient information to enable a high performance magnetic component design. At high operating frequencies the magnetic component suffers from nonuniform magnetic flux distribution. Therefore, accurate modelling of the magnetic material frequency characteristic, based on conductivity, permeability and permittivity, is essential for reliable design. This paper proposes a method to determine the electrical properties of MnZn ferrite at high frequency. The paper also presents complex permittivity vs. frequency characteristics for various ferrite materials. Fitted parameters for equivalent circuit models enable data to be used in any design algorithm or simulation tool.