Modeling Methodology of Magnetic Toroidal Cores for 3-D FEM Full-Wave Simulation up to 100 MHz

This article presents a full-wave 3-D FEM simulation methodology for magnetic toroidal cores up to 100 MHz. 3-D FEM simulation of magnetic toroidal cores has gained significant relevance in recent years. However, the use of magnetic materials in simulation presents some difficulties. Complex permeability is typically the only electromagnetic property used in magnetic toroidal cores' simulation. Nonetheless, recent results suggest that other properties must also be considered in high-frequency simulations. The presented methodology is particularly practical as it accurately models commercial cores easily. Electromagnetic properties valid for simulation are directly extracted from the cores with two simple setups. No complex fixtures or sample modification are required. Two ferrites (MnZn and NiZn) and a nanocrystalline core are studied. Complex permeability is characterized with a largely used method, and complex permittivity is extracted directly from the cores using the parallel plate capacitor method. With this methodology, cores' electromagnetic models are achieved, which are validated by comparing 3-D FEM simulations of several inductors with their measurements. Results lead to a simple and practical methodology to perform small-signal cores simulation in linear zone up to 100 MHz, which had not been achieved so far.