Experimental shaped reflector antenna

A shaped reflector antenna was designed using an aperture synthesis method. The antenna was designed to operate over the Ku band transmit frequencies (11.7 to 12.2 GHz). The design consists of a single Potter horn feeding a 28.34 in by 28.24 in. square aperture shaped reflector with a 26.15 in. effective focal length. It turns out that the phase front for the radiation pattern of the Potter horn feed is not spherical over the angular extent of the reflector. If the Potter horn feed had a true spherical phase front, then the measured phase would be constant, as was assumed in the calculated results. It is also suspected that the variation of this phase with frequency is the cause of the large frequency variation in the measured shaped reflector radiation patterns. Some preliminary work was done in which a shaped reflector radiation pattern was recalculated using a feed model that took into account phase variation.<>