Offset near-field Gregorian antenna scanning beam analysis

A method is presented for analyzing the offset near-field Gregorian antenna. The scanning capability of the antenna system (three dimensional) is demonstrated. The analysis employs geometrical optics ray-tracing techniques to transform feed-array amplitude and phase distributions into near-field Gregorian aperture distributions. Reflector-aperture field integration techniques are then employed to compute the related antenna pattern and gain characteristics. A preliminary study of the plane-wave spectrum (PWS) method applied for the near-field offset Gregorian reflectors is also included.