Algebraic Multigrid Combined With Domain Decomposition for the Finite Element Analysis of Large Scattering Problems

In the finite element analysis of electromagnetic scattering, a recent algebraic multigrid method (Aghabarati and Webb, “An Algebraic Multigrid Method for the Finite Element Analysis of Large Scattering Problems,” IEEE Trans. Antennas Propag., vol. 61, no, 2, pp. 809-817, Feb. 2013) has been shown to be an efficient way to solve the large, sparse matrix equation. However, the effectiveness of the method decreases as the electrical size of the problem increases. This limitation is overcome by combining it with a domain decomposition method (DDM). Exact solution on each domain is not needed: a single W-cycle of the multigrid method is sufficient. Results are presented for scattering of plane waves by conducting and dielectric objects, with dimensions ranging from 3 wavelengths to 20 wavelengths.