A memory-reduction scheme for the FFT T-matrix method [EM wave scattering applications]

We present a memory-reduction technique for the fast Fourier transformation (FFT) T-matrix method. The technique exploits the configuration- and Fourier-space symmetry relations of the transverse spherical multipole translation coefficients whose storage drives the memory requirement. The technique is capable of reducing the memory requirement by a factor of 6/spl sim/16 depending on the number of modes used and the spatial distribution of scatterers and is simple to implement in an existing FFT T-matrix code. We establish its accuracy and effectiveness by applying the technique to compute the RCS of aggregates of dielectric spheres.