Low side lobes in pencil-beam antennas

This paper describes an investigation of the radiation properties of two perfectly focussing devices: the paraboloid reflector and the hyperboloid dielectric lens excited at their focii by a short electric dipole and a short magnetic dipole and a plane wave source. The purpose of this investigation is to examine the radiation characteristics of these antennas which, at least in the limit of infinitesimal wavelengths t have no phase aberrations in the aperture field. The analysis is divided into two parts: (1) the aperture field: of the two antennas are first computed, and (2) the far-zone diffraction patterns are then determined. The power gain of the systems is obtained as a by-product of the diffraction pattern computation. Some experimental results are also discussed.