Cassegrainsymmetrical reflector
The reflector can be analyzed using the student version of GRASP available from TICRA using a Gaussian beam feed antenna.  The executable GRANETDS (Linux version) can be downloaded for the geometry parameters. To understand the geometry, see: C. Granet, Designing Axially Symmetric Cassegrain or Gregorian Dual Reflector Antennas from Combinations of Prescribed Geometric Parameters, IEEE Antenna and Propagation Magazine, Vol. 40, no. 2, April 1998, pp. 76-82 and Part 2, Vol. 40, no. 3, June 1998, pp. 82-87. A set of Fortran subroutines for this geometry is contained in the set: granet_equations.
A step-by-step presentation with audio tracks using student version of GRASP10 can be downloaded Cassegrain_10_audio_ppt with input files:  Cassegrain_GRASP.

sym_cass.gif

t