A Mixed Surface Volume Integral Formulation for the Modeling of High-Frequency Coreless Inductors

An original integral formulation dedicated to the high-frequency modeling of electromagnetic systems without magnetic materials is presented. The total current density (i.e., conduction plus displacement currents) is approached by facet elements so that resistive, inductive, and capacitive effects are all modeled. Furthermore, the method avoids the volume mesh of the conductors, which is too dense at high frequencies, due to the skin and proximity effects appearing, e.g., in wound inductors. Surface impedance boundary conditions are employed to that end. The formulation is general and suitable for nonsimply connected domains. It is first compared with the finite-element method on an academic test case, and is then experimentally validated on a coreless wound inductor, using an impedance analyzer.