On the inclusion of loss in time-domain solutions of electromagnetic interaction problems

A computational approach for including the effects of a dispersive loss in direct time-domain solutions for electromagnetic (EM) field problems is discussed. If such problems are solved in the frequency domain, a dispersive impedance that models the loss can be easily incorporated in the solution. In the time domain, this effect is taken into account through a convolution integral, which involves a distribution function that has properties between those of a Dirac delta function and a doublet. A few simple examples of these distribution functions are presented, and comments as to their use in calculations are made