On Spectral Content of Radiating Components of Electromagnetic Sources

This contribution deals with a spectral analysis of radiating components of a generic source which radiates a given field. This analysis, even if general, has a great relevance to inverse scattering problems, wherein some currents are induced in unknown obstacles due to the interaction with a known electromagnetic incident field and irradiate in turn another field, known as scattered field. The analysis has been detailed to both one-dimensional and two-dimensional geometries and allows to understand how the spectral contents can change depending on the dimension of the source support (which is exactly equal to the target support). Note that the understanding of spectral properties of radiating currents can be relevant not only to microwave imaging but also to antenna synthesis and diagnosis.