The uniqueness of inverse scattering problems, reciprocity principles, and nonradiating sources related to low-signature structures

This paper is about perfectly electrically conducting structures designed to produce negligible scattered power when exposed to a time-harmonic plane electromagnetic wave. The structures feature cavities capable of concealing objects. Theoretical investigations of the properties of the structures combined with accurate numerical computations lead to three key findings: the first concerns the uniqueness of the solution to an inverse scattering problem, the second establishes a reciprocity relation for the far-field scattering amplitude, and the third reveals the existence of non-radiating sources that generate substantial electromagnetic fields near the source region. The results have applications in low-observable technology.