Application of Gaussian Beam Summation Method inHigh-Frequency RCS of Complex Radar Targets

International audienceCaustics problem is inherent to classical highfrequency approximation such Geometrical Optics (GO),Geometric Theory of Diffraction (GTD), Uniform Theory ofDiffraction (UTD) and Equivalents Current Methods (MCE). Allthese developments propose numerical estimations of the EMfield scattered from reflection, diffraction, and multiplescattering from an object. In this paper we apply the Gaussianbeam summation technique (GBS) to simulate RCS of radartarget, especially for 5 to 10 wavelengths sizes. Gaussian beamsare asymptotic solutions of the Helmholtz equation within theparaxial approximation. Since they are insensitive to raytransition region, several techniques based on Gaussian beam areused to evaluate high frequency EM wave equation, whichovercome partially or fully the difficulties of singular regions(caustics, zero field in shadow zones). In this formulation, thecomplete wave field at a receiver is evaluated as superposition ofGaussian beams concentrated close to rays emerging from thetarget, passing in a small neighborhood of the receiver. When theincident field strikes the edges, the diffraction is accounted in acomplex weighing function, applying the geometrical theory ofdiffraction (GTD). Simulation with canonical target shown willbe compared to asymptotic methods (Physical Optic) andrigorous method (Method of moment