Philip H. Jones, Onofrio M. Maragò & Giovanni Volpe
Fig. 4.5 — From near field to far field
The electromagnetic near field, E defined on the plane z = 0, and the far field, Eff, are connected by Eq. (4.13), so that the angular component of the former in the xy-plane with wavevector k corresponds to a propagating plane wave in the far field along the direction of k.