Far-field patterns of ultra high gain antenna arrays of finite size

The author attempts to establish, by rigorous formal and numerical analysis, the validity of recent claims purporting the practical feasibility of so-called nondiffracting beams, at essentially any frequency across the electromagnetic spectrum, including microwaves, millimeter waves, and infrared and visible light. The objective is to determine whether any physically realizable, finite size planar aperture distribution can be defined that can be proved to even only approximate, within some acceptable tolerance, the radiation characteristics of a nondiffracting beam. The approach has been to synthesize such a planar aperture distribution in terms of a vectorial expansion in cylindrical modes, while imposing the constraint of zero average radial energy flow everywhere in the half space facing the aperture. An attempt is being made to determine the effects on the far field pattern of truncating the circular aperture to some optimum finite radius.<>