On the testing of the magnetic field integral equation with RWG basis functions in method of moments

For electromagnetic analysis using method of moments (MoM), three-dimensional (3-D) arbitrary conducting surfaces are often discretized in Rao, Wilton and Glisson basis functions. The MoM Galerkin discretization of the magnetic field integral equation (MFIE) includes a factor /spl Omega//sub 0/ equal to the solid angle external to the surface at the testing points, which is 2/spl pi/ everywhere on the surface of the object, except at the edges or tips that constitute a set of zero measure. However, the standard formulation of the MFIE with /spl Omega//sub 0/=2/spl pi/ leads to inaccurate results for electrically small sharp-edged objects. This paper presents a correction to the /spl Omega//sub 0/ factor that, using Galerkin testing in the MFIE, gives accuracy comparable to the electric field integral equation (EFIE), which behaves very well for small sharp-edged objects and can be taken as a reference.

I. Introduction

Electric and magnetic field integral equations [2] are widely used in conjunction with Method of Moments (MoM) discretization [1] for the numerical analysis of electromagnetic radiation and scattering. The MoM Galerkin discretization of the electric field integral equation (EFIE) for three-dimensional (3-D) arbitrary surfaces was presented by Rao, Wilton and Glisson (RWG) in the well-known reference [3]. The linear triangle basis function presented in [3] will be denoted here as RWG basis function. An analogous formulation for the magnetic field integral equation (MFIE) for 3-D arbitrary surfaces was later developed [4].