Designing classical offset Cassegrain or Gregorian dual-reflector antennas from combinations of prescribed geometric parameters. Part 2: feed-horn blockage conditions

This paper is a short appendix to [C. Garnet, June 2002], where a classical offset Cassegrain of Gregorian dual-reflector antennas were designed from combinations of prescribed geometric parameters. However, in [C. Garnet, June 2002], the model assumed a point-source feed, and did not take into account the physical dimensions of the feed horn needed to illuminate the subreflector. Now, as in [C. Garnet, April 1998], we consider a feed horn. The feed horn is therefore simulated as a cone, which is a fair description in most cases, and is sufficient in the initial design stage of an antenna.