EFFICIENT NUMERICAL COMPUTATION OF SINGULAR-INTEGRALS WITH APPLICATIONS TO ELECTROMAGNETICS

Efficient schemes to accurately compute singular integrals are present ed. The singularity is removed prior to numerical integration, using a change of variables, integration by parts, or a combination of both. A change of variables eliminates power-law singularities of the type x (-alpha), alpha < 1 and fenders the integrand well behaved, Similarly, a logarithmic singularity of the form In x is eliminated either by di rect integration by parts or by multiplying and dividing the integrand by In x followed by integration by parts. Cauchy-type singularities a re also removed by integrating the singular term by parts twice. In al l cases, the remaining integrand is well behaved and lends itself to s traightforward numerical integration. The technique is applied to scat tering from a perfectly conducting cylinder. Comparison of the numeric al and exact solutions show the stability of the technique.