Early warning radar antennas

The current military requirements for the detection of missiles at ranges of 2000 to 3000 miles has led to the need for high-gain antennas at wavelengths of approximately one meter. Because of the unwieldy size of such antennas, the authors have been investigating antenna types in which the beam directional control can be accomplished by switching the feed point rather than by moving the entire structure. Three main large-scale types have been considered: a flat "pancake" structure in which surface wave radiation is utilized, a luneberg lens structure utilizing artificial and loaded dielectrics, and a spherical structure employing a unique polarization relationship to provide a folded paraboloidal reflector effect.