EFFECTS OF A FIN EDGE CLOSE TO A POINT CAUSTIC OF A GREGORIAN ANTENNA

The problem of edge diffraction close to a point caustic is analyzed i n a typical dual-reflector Gregorian antenna in offset configuration. The diffraction phenomenon is produced by a perfectly conducting fin l ocated between the feeder and the main reflector. This fin is sometime s used to reduce the coupling between the primary feed and the main re flector. For the sake of simplicity, the two-dimensional case is studi ed here, but the present technique can also be applied to practical th ree-dimensional configurations. (C) 1997 John Wiley & Sons, Inc.