The Wound Foil Inductor is an important example of inductive components with appreciable internal capacitance. It is examined from three viewpoints – electromagnetic field theory, distributed-parameter (or transmission-line), and lumped equivalent circuit. The analyses are compared, particularly in terms of phase gradients within a component, and the relationship between a two-dimensional field analysis and the now established lumped model is derived.
A method for computing surge impedance of transmission line tower by electromagnetic field theory.