Scattering solution from a large 2-D inhomogeneous scatterer by a fast recursive algorithm

A fast recursive algorithm has been applied to solve the scattering solution of a large 2D inhomogeneous body for TM (transverse magnetic) waves. The inhomogeneous body is first divided into N subscatterers. The algorithm uses an aggregate T matrix and translation formulas for the solution of n+1 subscatterers from the solution for n subscatterers. The computational complexity of the algorithms is of O(NMP/sup 2/), where NM is the number of unknowns and P is the number of harmonics required in the translation formulas. The memory requirement is proportional to the number of unknowns. The algorithm has been used for the scattering solution of a 10 lambda -diameter 2-D scatterer with about 12000 unknowns, taking about 30 s on a CRAY-2 supercomputer.<>