Radar cross section reduction by lumped, linear, passive loading

A general analysis describing total power scattered from lossy, electrically linear bodies of arbitrary shape, excited by single-frequency plane waves, is modified to treat bistatic scattered power, p(sub sc), in a specified solid angle. Formulas are given for the passive load at a selected port to minimize p(sub sc) in terms of four real radiation field parameters and the input impedance. The analysis is illustrated for a thin-wire aircraft model, lambda/2 long. p(sub sc) in a 60 deg. cone is first minimized for nose-on incidence of a circularly-polarized wave, and then reduced for many incident waves by lumped loading at two ports. An iterative scheme was employed to converge on the loads. Even the simple loading scheme employed reduced p(sub sc) by at least 12.8 dB for each of the 56 directions of incidence within the 60 deg. scatter cone.