Conceptual spaceborne Ka-band spotlight synthetic aperture radar with reconfigurable aperture

Two principal objectives of this investigation are: a) to produce using a reconfigurable aperture circular beam footprints for grazing angles from 15/spl deg/ to 70/spl deg/, and b) to maintain high efficiency high-power 35 GHz solid-state devices in a feed array. An elliptical reflector 8.51 m high and 2.9 m wide is proposed with a near-zone programmable, transmit-receive phased array feed in a beam waveguide to deliver 25.5 w/m/sup 2/ at the radiating aperture. By redirecting the beam to track a particular area, called the "spotlight-mode", fine azimuth resolution and multi-look images can be produced. A 700 km altitude orbit is assumed and the resolution goal is 1.0 m.