A Study on Characteristic Mode Equations of Radiation Problems Contrasted with Scattering Problems for Dielectric Bodies

This paper is concerned with the extractions of electromagnetic characteristic modes (CMs) for lossless dielectric bodies, which spurious are prone to generate using traditional definition CMs based on Poggio–Miller–Chang–Harrington–Wu–Tsai (PMCHWT) equations. It found that impedance matrix PMCHWT equations cannot distinguish (i) domain body and background (ii) from excitation source was applied. If system taken as a scattering problem, solutions reverse media i.e., exchanging space. However, if radiation no appropriate meet specified boundary conditions obtained. These phenomena indicate developed systems not suitable systems. To clarify issue, four cases sources in either examined. The distinct essence, but them. As result, definitions should be given along their specific conditions. Especially, problems we consider here show inside material object properly defined order distinguished problems.