Evaluation of High-Frequency Electromagnetic Scattering via High-Order Multiple-Scattering Integral Asymptotics

The present text proposes development of a new approach for the numerical evaluation of high-frequency electromagnetic scattering for structures of interest to DoD. This approach, which relies on high-order high-frequency integral asymptotics, is entirelyrigorous: it should account fully for all scatterer complexities and all electromagnetic effects - including multiple-scattering, diffraction, caustics, creeping waves, shadowing, penumbrae, etc. The high-order integral methods mentioned above wereintroduced recently by this PI and collaborators as a component of a rough-surface multi-scale solver. The goal of the work proposed here is to determine the merit of high-order asymptotic methods for evaluation of scattering from complex boundedscatterers, including air and land vehicles. Unlike rough surfaces, bounded scatterers: a) give rise to multiple scattering effects which cannot be accounted for by previous analytic continuation methods, b) they require complexgeometric descriptions, and c) they necessarily give rise to complex shadowing processes.We expect the proposed work will result in technologies allowing for accurate evaluation of high-frequency bounded-body scattering within the proposed high-order asymptotic framework. The successful completion of this project will lead to significantimprovements in the description of high-frequency scattering processes: an area of great importance for both national security and commercial concerns.As indicated in the AF01T009 topical description, the electromagnetic scattering attributes ofactual-size inventory usually needs to be obtained by high frequency approximations - the previous versions of which suffer from various shortcomings. The proposed algorithms avoid all such shortcomings, which arise mainly from use of ray tracing orneglect of multiple-scattering and diffraction effects, by introducing a paradigm which accounts fully for multiple scattering and shadow boundaries, and which does not rely on ray tracing in any way. The military and commercial applications of suchalgorithms are very numerous indeed: they range from remote sensing of vehicles to mapping, antenna design, altimetry and communications. Thus, the successful completion of the proposed work will lead to significant benefits in a wide variety of areas,with a very substantial potential for commercial impact.