Suppression of field projection error in EPA at low frequencies by augmentation method

Abstract

Equivalence principle algorithm (EPA) using the high-order field point sampling scheme [1] has low frequency breakdown problem when the frequency becomes very low [2]. The low frequency problem is usually remedied by the loop-tree decomposition method [3]. However, this method suffers from the need to search for loops. Finding loops for the subdomains in EPA, especially for connected subdomains cases, becomes very involved. In recent years, researchers have proposed the current and charge equations for low frequency breakdown problems [4, 5, 6]. These methods can improve the conditioning of the matrix equations. Moreover, they are not burdened by loop search. This paper proposes an augmented EPA formulation. It introduces charge density unknowns on the equivalence surface (ES). Hence, the low frequency breakdown of field projection operators in EPA is removed. The new augmented scheme is stable in a wide frequency range. © 2010 IEEE.