Focal region characteristics of offset fed reflectors

The focal region characteristics of offset fed reflector antennas have been investigated both analytically and experimentally. In order for offset reflectors to have analogous focal region properties to those of front fed parabolic reflectors, an offset axis and an offset focal plane are defined. The definitions of the offset axis and offset focal plane are essential for satisfactory operations of offset reflectors illuminated by a cluster of feeds. Numerical results using physical optics approximation are presented to show the dependence of the beam deviation factor of offset reflectors upon the edge angle ( ) and the orientation of the feed axis( ).