Partially adaptive phased array fed cylindrical reflector technique for high performance synthetic aperture radar system

Spaceborne microwave radar instruments demand a high-performance antenna with a large aperture. Particularly challenging in the specifications for the technical requirements of the antenna is to maintain radiation patterns with low sidelobe levels over wide scan angles in the across track direction, and to obtain the appropriate antenna beamwidth and directivity for a field of view from nadir, so that a ground swath size is properly illuminated. We present a novel antenna design technique to achieve and enhance the capabilities for such an instrument. A cylindrical reflector fed with a partially adaptive phased array feed is proposed. It is shown that high-versatility reflector patterns are obtained with amplitude and phase control of only the edge elements, partially adaptive, in the array.