CURRENT-MODEL ANALYSIS OF ELECTROMAGNETIC SCATTERING FROM OBJECTS CONTAINING A VARIETY OF LENGTH SCALES

Fictitious-current models have been applied extensive in recent years to a variety of time-harmonic electromagnetic-wave scattering problems . An extension of the current-model technique is introduced that facil itates the solution to problems subsuming scatterers that contain a va riety of length scales. This extension is in tune with the current-mod el technique's philosophy of using simple current sources whose fields are analytically derivable. The approach amounts to letting the coord inates of some of the source centers assume complex values. Positioned in complex space, the simple current sources radiate beam-type fields that are more localized and that are better approximations of the sca ttering from the smooth expanses of the object. The coordinates of the other source centers retain their conventional real values. These lat ter current sources are used, of course, to approximate the fields in the vicinity of the more rapidly varying expanses of the object. We us e the new approach to analyze electromagnetic scattering by an object comprising two adjacent perfectly conducting spheres of different size . We find that it renders the solution computationally more effective at the expense of only a slight increase in its complexity.