Hybridization of curvilinear time-domain integral equation and time-domain optical methods for electromagnetic scattering analysis

Full-field solutions for scattering and similar problems become prohibitively expensive for electrically large bodies. Fortunately, broadly “optical” methods become accurate as larger bodies are considered. Often, however, large bodies have significant features that are not electrically large and here hybrid approaches are appropriate. We present a novel hybridization of time-domain integral equation methods with time-domain physical optics (PO). For both methods, an isoparametric curvilinear treatment is adopted. The application of the approach is demonstrated by investigating the convergence of the solution for a pulse incident on a large target with a small feature (a 16-pulsewidth plate with a ~1/3-pulsewidth sphere placed centrally just in front of it). It is demonstrated that a full-field solution for the sphere and a fairly small region around the sphere, coupled with the PO solution of the remainder of the plate, produces a converged prediction of the time-dependent fields