A hybrid FDTD-MoM procedure for the modeling of electromagnetic radiation from cavity-backed apertures

Electromagnetic emission from a cabinet which encloses radiofrequency equipments, such as avionic transmitters and high speed digital computers, requires proper consideration during the system design task. At a frequency of hundreds of megahertz, apertures for air cooling, cable connectors and upgrades are not electrically small and act as possible sources of radiation outside the cabinet. A segmentation numerical method is presented for the computation of electromagnetic emission from apertures of size comparable with the wavelength. The procedure requires that the cavity interior, including any object, is modelled by the finite difference time domain, and that the moment method is used for the solution of the exterior problem. A reaction theorem approach allows the coupling of the two methods. The proposed procedure reduces the computational effort in comparison with a full FDTD solution and allows partial reuse of already computed electromagnetic data.