Array feeds for the compact range

The authors examine a potential alternative to reflector edge treatment in which the conventional single-element feed is replaced with an array. The reflector is designed for optimal geometrical-optics performance, so that a larger quiet zone is available at high frequencies. Two approaches to the design of the array are presented. The first is an optimization technique based upon reciprocity and implemented using the conjugate field matching method, while the second is based upon beam shaping techniques. For this study, the reflector is assumed to be an offset paraboloid having a circular rim, and all the array elements are situated in the focal plane. Improvement over the single point source feed is obtained, even at frequencies 10% above and below the design frequency.<>