Statistical signal analysis for the inverse source problem of electromagnetics

A statistical signal analysis for the inverse source problem of electromagnetics is given. This correspondence considers the problem of estimating either the near field or the radiating current distribution from a measurement of the far field. The solution is derived via a linear operator formalism, and the ill-posedness of the reconstruction is quantified by using the Cramer-Rao lower bound, which is explicitly given in terms of the multipole expansion of the electromagnetic field. A numerical study is included to illustrate the theoretical results.