Incoherent scattering from dense clouds of wire dipoles

The back scattering of radar waves by clouds of chaff, or dipoles, is characterized by the radar cross section (RCS) of the cloud. The determination of the RCS of large sparse dipole clouds is straightforward in most instances [1]. If the dipole cloud is dense, however, the part of the cloud closest to the source of incident radiation will shield the distant regions of the cloud so that less incident energy will reach them. In a study of coherent scattering from an infinite slab of randomly placed dipoles with random orientation, the complete field solution and the RCS were obtained using a method which considered the dipole cloud as a homogeneous material with conductivity that depends on the density and propagation frequency f [2]. This coherent solution was based on the boundary value solution of a system of differential equations. The idealized slab geometry utilized in [2] will be extended herein to more general cases. It is shown that for many cases of interest, the coherent RCS of a chaff cloud can be found without solving a complete boundary value problem. This is extended to the incoherent scattering solution for a chaff cloud of general density.