COMBINING AN EXTRAPOLATION TECHNIQUE WITH THE METHOD OF MOMENTS FOR SOLVING LARGE SCATTERING PROBLEMS INVOLVING BODIES OF REVOLUTION

The purpose of this work is to combine an extrapolation technique with the method of moments (MoM) to solve scattering problems involving la rge bodies, It has been shown in a previous work that the current indu ced on the smooth parts of large scatterers may be represented as a se ries of complex exponential functions with a few terms, Based on this concept, a hybrid set of basis functions is constructed using entire d omain functions of complex exponential type on the smooth portion of t he scatterer, complemented by subdomain basis functions near edges and discontinuities. An extrapolation procedure is developed in which the scattering problem is first solved for a portion of the scatterer usi ng the conventional MoM. Next, a set of entire-domain basis functions, whose behavior could be extrapolated with an increase in the size of the scatterer, is extracted from this original solution, The procedure outlined has the very desirable feature that the total number of basi s functions remains unchanged even as the scatterer size is increased, allowing for large scatterers to be handled with a relatively small n umber of unknowns, The extrapolation technique is applied to scatterin g problems from bodies of revolution (BOR's), and numerical results fo r an open cylinder and a barrel-shaped BOR are presented.