On the information content of the radiated fields in the near zone over bounded domains

We investigate the problem of determining the number of degrees of freedom of radiated fields. In particular, this analysis concerns the determination of the `information content' provided by the knowledge of the field over bounded observation domains located both in the Fresnel zone and in the near zone, when only a priori information about the geometrical parameters of the planar source and of the planar observation domains is known.