Total-Field versus Scattered-Field Finite-Difference Codes: A Comparative Assessment

This paper deals with time-domain finite-difference (TDFD) techniques for solutions of Maxwell's equations. Two types of algorithms are treated: scattered-field algorithms in which the incident fields (E_i,H_i), are analytically known but the scattered fields (E_s,H_s) must be computed with TDFD methods, and total-field calculations in which total fields (E_T,H_T) are found by TDFD techniques. Nonlinear problems and heavily shielded cavities can only be treated with the total-field approach. The price of this generality is an increase in mathematical complexity and computational cost.