Backscatter Radar Cross Section Analysis of Chaff Using the Sequential Loading Method

A new method of computing the radar cross section (RCS) of chaff particles and spherical chaff clouds is proposed using the sequential loading method (SLM). For the first time, the SLM has been used to compute the RCS of chaff particles for any aspect angle and polarization, over a broad range of lengths and frequencies, including resistive loss. One of the advantages of the SLM is its speed: in this work, the SLM computes the current flowing on a chaff particle from 2 to 29.5 GHz at least 80 times faster than a method of moments (MoMs) solution. A new spherical chaff cloud shielding model based on the SLM is then presented to rapidly compute the chaff cloud RCS as a function of its density. The results show that shielding, in addition to mutual coupling, is responsible for the nonlinear departure of the cloud’s RCS as a function of its density. A new rule based on the optical depth parameter is proposed to consistently estimate the upper density limit at which shielding becomes significant.