An Efficient Analysis of Scattering From Randomly Distributed Obstacles Using an Accurate Recursive Aggregated Centered T-Matrix Algorithm

An efficient recursive aggregated centered transition matrix (T-matrix) algorithm (RACTMA) to analyze electromagnetic scattering from many randomly distributed obstacles is derived. The algorithm is based on the scatterer-centered T-matrix formalism and is accelerated using the aggregation concept—unlike other approaches—without violating the addition theorems. An analytical derivation for the T-matrix of multiple cylinders together with the details of the computational complexity are given. Scattering by more than 3000 noncircular elements is numerically studied, and the results for the scattered fields are compared with those obtained by a well-established recursive T-matrix algorithm and, to demonstrate a proper convergence, the results are also compared with a commercial finite element method (FEM)-based full-wave solver. The results show a perfect agreement and demonstrate a high computational efficiency of the proposed semianalytical formalism for normal and oblique incidences. The optical theorem and the reciprocity relationship are fully satisfied confirming the accuracy and numerical stability of the approach.