Singularity Subtraction for Nearly Singular Integrals on Curvilinear Triangular Elements

This letter proposes a general singularity subtraction scheme to handle nearly singular 2-D integrals on curved triangular elements arising in high order method of moments (MoM) solution to surface integral equations. The approach works for kernels with various orders of singularity, and has very fast convergence. Comparisons are made between the proposed approach and the singularity cancellation schemes.