A Kernel-independent Fast Direct Solution of Surface Integral Equations for Conducting Objects

We propose a fast direct solver for surface electric field integral equation (EFIE) with a kernel-independent compression method for electromagnetic scattering from conducting objects. Based on the strong admissibility condition in which only the far-field interactions are compressed, equivalences are introduced for the approximation with higher computational efficiency than the weak admissibility condition. Different kinds of elimination matrices are introduced to eliminate the redundant parts of admissible and in admissible blocks and consequently the inversion of the system matrix is obtained by the multiplication of a series of matrices arising from the factorization process. A monostatic RCS result verifies the accuracy of our proposed method.