Abstract: A space-fed, flat, reflectarray antenna apparatus for providing a desired degree of phase shift to a received electromagnetic wave to form a narrow beamwidth signal. The reflectarray antenna, in one form, is provided as a dual reflection antenna having a polarization sensitive subreflector and a reflectarray element spaced apart from the subreflector. The reflectarray element includes a large plurality of independent patch antenna units which each form antenna cells. Each patch antenna unit includes a vertical polarization sensitive antenna, a horizontal polarization sensitive antenna and a microstrip transmission line conjoining the two antennas. The microstrip transmission line of each antenna unit has a predetermined length intended to provide a predetermined degree of phase shift.

Abstract: A radar jamming detection system is suitable for recognizing and distinguishing the presence of jamming and, particularly, terrain bounce jamming. The radar system includes a transmitter and a receiver. The receiver receives true radar skin return signals, in addition to ground clutter signals and jamming signals. The true radar skin return signals and ground clutter signals are recognizable in accordance with a predetermined receiver passband. Estimated target location, velocity and frequency data, as provided by a cueing radar, is used to set up the receiver passband for the radar detection system. Ground clutter range and angle measurements are used to determine an estimated ground range at the jammer angle, which is then compared with the cue range to determine if the received signals are terrain bounce jamming signals.