Stabilizing the E-Field Integral Equation at the internal resonances through the computation of its numerical null space

In this paper a technique to protect the Method of Moments solution of the E-Field Integral Equation (EFIE) for the scattering by conducting body from effects of its internal resonances, is presented. This method is based on the evaluation of the numerical null space K of the discretized EFIE operator. In order to verify its effectiveness, results for the plane wave scattering from a perfect conducting cube are presented. It is shown that the proposed method is able to give the correct value of the RCS even in presence of the interior resonances.