Sparse-matrix approach to the method-of-moments solution of electromagnetic problems

When a body is several wavelengths long, the full matrix required in the method-of-moments solution of Maxwell´s equations of electromagnetic theory is too large to be handled economically by present-day computers. A method by which this full matrix is reduced to a sparse matrix is outlined. This approach works best for open structures composed of long wires. It does not work so well for a solid surface. This is illustrated by means of radar-cross-section calculations for some simple shapes.