A progressive numerical method and its application to large field problems in antennas and electromagnetic scattering

It is shown that the numerical solution of electromagnetic scattering problems using moment methods can be carried out in a progressive manner by dividing the scattering surface into several small regions. The technique reduces the large matrix of the conventional moment method into several small matrices on the regions and enables one to solve easily the problem of scattering by very large objects. The accuracy of the method and the criteria for controlling computational errors are examined by its application to two-dimensional problems. Both parallel and perpendicular polarizations are assumed and the behaviour of the solutions for both smooth and singular field distributions on circular cylinders and prisms is studied. It is found that the surface distributions, such as induced currents, may be obtained more accurately by this method than the conventional moment method. The accuracy of the far fields, however, are generally of the same order for both methods. For convenience and brevity, the term PNM is used to refer to the method throughout this paper.