Time-Domain Synthesis of Broadband Absorptive Coatings for Two-Dimensional Conducting Targets

A new time-domain synthesis approach is introduced for Broadband absorptive coatings suitable for radar cross section (RCS) management. The new algorithm involves a finite-difference time-domain (FDTD) forward-scattering represention of Maxwell's curl equations in a numerical feedback loop with the Levenberg-Marquardt (L-M) nonlinear optimization routine. L-M is used to adjust many geometric and constitutive parameters that characterize a target, while FDTD is used to obtain the Broadband bistatic RCS response for each target adjustment. A recursive improvement process is established to minimize the Broadband RCS response over a selected range of bistatic angles using the available engineering degrees of freedom. The solution is valid over the potentially broad bandwidth (frequency decade or more) of the illuminating pulse used in the FDTD computational model. Examples of this method are provided in the area of RCS management for canonical two-dimensional conducting targets.