On a fundamental principle in the theory of planar antennas

General principle is presented which states that all of the properties of any planar antenna can be determined completely from any piece of its TE and TM partial pattern functions. The principle is based on the analytic properties of the pattern functions and on the fact that the aperture and pattern functions are related through the Fourier integral. It applies to much of antenna theory, transient as well as steady state. An interesting application is an analytic extension of the classical Poynting vector method as a means for determining input reactance, in addition to radiation resistance, of an antenna from its radiation pattern.