ABSTRACT
The art of the electrical engineering design partly relies on the ability to properly model the physical structure under consideration. Good models enable an efficient and accurate analysis, so that designers can reach their goals with a few iterations on the models and, usually, a few steps of experimental verification. Most electrical and electronic engineers use circuit-theory models to analyze various passive and active circuits. Such models are simple and straightforward to implement, they do not require bulky theoretical background, and they are easy to visualize. In principle, the field vectors can be arbitrary functions of time. For engineering applications, it is often sufficient to assume a steady-state regime. Numerical solutions of electromagnetic field problems are usually classified into two groups. The first one attacks directly electromagnetic fields, and the second one attacks the field sources. The piecewise-constant approximation is discontinuous.
