Calculation of the emission from a plane-aperture radiator by systems-analysis methods

Systems-analysis techniques from information and control theory are applied to antenna radiation and design problems. The aperture plane and a parallel measurement plane are treated as a linear shift-invariant system described by a Green's function and its transfer function, while the Huygens principle is used to calculate the radiation as the response of the system to a given aperture current distribution. The technique is applied to the optimization of a focusing radiator, and graphs of the results are included.