Hierarchical Additive Basis Functions for the Finite-Element Treatment of Corner Singularities

Scalar and vector basis functions are developed for modeling corner singularities in electromagnetic fields. These functions are additive as opposed to substitutive; instead of replacing certain basis functions, singular bases are superimposed with a full set of existing hierarchical nonsingular polynomial basis functions to form the representation. The functions are described for triangular cells, and results are provided to illustrate their performance in terms of solution accuracy and matrix condition number