Multi-level fast multipole for antenna modelling

The method of moments (MoM) is considered as the benchmark against which other full-wave electromagnetic modelling techniques are compared. Unfortunately, this technique carries a heavy computational burden, which limits its applicability to relatively small problems. The fast multipole method (FMM) (see Coifman, R. et al., IEEE Antennas and Propag. Magazine, vol.35, no.3, p.7-12, 1993), reduces the computational burden considerably and can be applied on multiple levels (see Song, J.M. et al., IEEE Trans. Antennas and Propag., vol.45, no.10, p.1488-93, 1997). The overhead for the multi-level fast multipole algorithm (MLFMA) is greater than the direct application of MoM for small problems, but the benefits become apparent for problems with greater than approximately 2000 unknowns. An implementation of MLFMA has been developed. This software has been ported to parallel computing platforms using the MPI (message passing interface) library. The greatest benefits can be gained by using this technique on the most powerful computers. The scattering from a whole fighter aircraft can be calculated up to GHz frequencies using a parallel computer. The software is being developed to add the capability to model installed antenna performance. Some of the technical challenges are described.