Advanced phased arrays for airborne radiometric imagers

Airborne high resolution and high sensitivity radiometric systems operating at mm (90 GHz) wavelengths hold the promise for high performance, all-weather ground surveillance and reconnaissance applications. The systems use planar phased arrays which generate N rows of staring antenna beams along lines perpendicular to the flight direction, so that a target is seen consecutively by N antenna beams; additionally the same systems can have substantial bandwidths. The beam forming function can be implemented either by using digital or analog techniques in conjunction with the Mills 0°-180° phase switching technique which greatly simplifies the beamforming network