Combining Loop-Tree decomposition with Accelerated Cartesian Expansion

It is well-known that fast solver designed for electrically large problem such as Multilevel Fast Multipole Algorithm (MLFMA) breaks down when applied for low frequency problem. In this paper, we combines Loop-Tree decomposition with the recently developed Accelerated Cartesian Expansion (ACE) to achieve large scale computation of low frequency scattering from perfect electrically conducting (PEC) objects. Basis rearrangement and multi-step iteration scheme are also implemented to improve the convergence of iterative solver. Numerical result validates the proposed method.