Propagation and radiation behaviour of corrugated feeds. Part 2: Corrugated-conical-horn feed

A theoretical and experimental investigation of the radiation behaviour of conical corrugated horns is described. The horn-aperture field is determined using spherical-mode analysis, and the radiation pattern is obtained by two methods, one of which employs a Kirchhoff-Huygen integration over a constant-phase surface at the mouth of the horn, and the other of which employs an expansion of the aperture field in terms of TE and TM spherical modes of freespace. Excellent agreement is obtained between the two methods and with experimental results. A theoretical investigation is reported of the use of lenses to correct the phase of a conical corrugated horn. Finally, the performance of paraboloid antennas using corrugated horns as feeds is briefly discussed.