A combined AIM-SFX approach for large complex arrays

One of the most successful approaches to the method of moments (MoM) analysis of large problems is that adopted by the so called "fast methods"; they are based on the use of iterative solvers, and essentially aim at the reduction of the cost and memory occupation needed at each step of the iterative algorithm. The complexity of one iteration step in time and memory occupation is reduced up to the order of 0(Nlog2N) in the multilevel FMM or in the sparse matrix / adaptive integral method SM/AIM. Here we propose a combination of a fast method with one of the techniques based on the compression matrix, in order to take advantage of the complementary properties of the two approaches and further enhancing the numerical properties of the resulting hybrid technique. In particular, we employ the fast matrix-vector properties of SM/AIM to speed the matrix filling of the SFX method. The resulting approach is iteration-free, but significantly faster.