An array feed approach to compact range reflector design

A novel methodology is presented for the design of array feeds for compact range reflectors. The principal design strategy is to illuminate the rim of a standard, circular-aperture reflector with an array pattern null. This results in a reduction in the level of edge-diffracted fields present in the quiet zone. Since low-frequency performance is improved without dedicating reflector surface area to edge treatment, the potential quiet zone size is maximized. Implementation of the technique requires only a few real-valued array excitation coefficients. It is demonstrated that various quiet zone field performance trade-offs can be made by varying either the excitation coefficients or the array size. The quality of the quiet zone field is compared with that of a uniformly illuminated serrated reflector. The operational bandwidth and the effects of both random and systematic array excitation coefficient errors are evaluated.>