RECURSIVE T-MATRIX METHODS FOR SCATTERING FROM MULTIPLE DIELECTRIC AND METALLIC OBJECTS

We present an efficient, stable, recursive T-matrix algorithm to calcu late the scattered field from a heterogeneous collection of spatially separated objects. The algorithm is based on the use of higher order m ultipole expansions than those typically employed in recursive T-matri x techniques. The use of these expansions introduces instability in th e recursions developed in [5] and [6], specifically in the case of nea r-field computations. By modifying the original recursive algorithm to avoid these instabilities, we arrive at a flexible and efficient forw ard solver appropriate for a variety of scattering calculations. The a lgorithm can be applied when the objects are dielectric, metallic, or a mixture of both. We verify this method for cases where the scatterer s are electrically small (fraction of a wavelength) or relatively larg e (12 lambda). While developed for near-field calculation, this approa ch is applicable for far-field problems as well. Finally, we demonstra te that the computational complexity of this approach compares favorab ly with comparable recursive algorithms.