Theory of the Annular Slot Antenna Based on Duality

The general theory of annular slot antennas is developed in a lucid manner. The treatment is novel in that no Green's functions or contour integrations arise. The principle of duality is employed. Topics discussed include formulation of the integral equation for the aperture field and derivations of the leading term in the near- and far-zone fields and effective height. The theory has application in calibrating near-zone field strength instrumentation and in determining the response of an unsheathed coaxial cable connector mounted flush with the skin of a missile to intense plane-wave electromagnetic field pulses.