A Multi-Resolution Preconditioner for Nonconformal Meshes in the MoM Solution of Large Multiscale Structures

The article presents a multi-resolution (MR) preconditioner able to improve the solution convergence, via the method of moments (MoM) and the multilevel fast multipole algorithm (MLFMA), in the case of nonconformal meshes applying the multi-branch Rao–Wilton–Glisson (MB-RWG) basis functions. The proposed preconditioner enables, for the first time, an automatic multilevel quasi-Helmholtz decomposition on nonconforming meshes, including also the generation of the topological (global) loop functions. Moreover, the generation of the proposed preconditioning scheme is fully parallelized in a multicore shared-memory environment. Numerical results show the great flexibility of this approach for the solution of electrically large multiscale objects including h-refinement discretizations.