THE FALLACY OF EDGE ELEMENTS

The present paper critically investigates the use of edge elements for computing electromagnetic fields. The application of edge elements in methods based on the use of vector potentials as well as in methods t hat compute electric and/or magnetic fields directly will be covered. In particular the popular idea that edge elements eliminate spurious s olutions will be refuted. This erroneous idea is replaced by the insig ht that spurious solutions can be eliminated only by a proper finite-e lement formulation. A reference is made to alternative approaches, one of them introducing a new type of element, the so-called generalized Cartesian element, that combines the advantages of the classical Carte sian (nodal) elements with the ability of edge elements to allow the r epresentation of discontinuities.