ANALYSIS OF ELECTROMAGNETIC SCATTERING BY CYLINDERS WITH EDGES USING A HYBRID MOMENT METHOD

The paper presents a method to improve the applicability of the fictit ious source-model technique to metallic cylinders with sharp edges. Pr evious approaches have required that some of the fictitious currents b e located in the proximity of the edges, so as to span the rapidly var ying field in these regions. While success has been reported, the accu racy of these solutions has often been dependent on a judicious choice of source location. In the paper, the fields in the vicinity of the e dges are expanded in terms of analytical solutions of the infinite-wed ge problem, while the field beyond these near-edge regions is expanded using fictitious current filaments. The operator equations, for the e quivalent problem obtained in this manner, are imposed at the boundary between these regions. As the fields on this boundary are inherently slowly varying, the solution is less sensitive to the location of the fictitious current sources. Moreover, higher accuracy in calculating n ear-field quantities such as the induced surface current can be attain ed with a smaller number of expansion functions.