Dragonian dual reflector
The reflector can be analyzed using the student version of GRASP9 available from TICRA (www.ticra.com) using a Gaussian beam feed antenna.  A step-by-step presentation can be downloaded: Dragonian_ppt_audio with an audio track or Dragonian10_ppt_audio using GRASP10 along with a set of GRASP files: Dragonian_GRASP.  The executable GRANETDR (Linux version) can be downloaded for the geometry parameters. To understand the geometry, see: C. Granet, Designing Classical Dragonian Offset Dual-Reflector Antennas from Combinations of Prescribed Geometric Parameters, IEEE Antennas and Propagation Magazine, Vol. 43, no. 6, December 2001, pp. 100-107. A set of Fortran subroutines for this geometry is contained in the set: granet_equations.