Trends in Phased Arrays

The advent of the ballistic missile threat has promoted interest in a complex form of RADAR commonly called a "phased array. " These RADARs, instead of using a single electrically large antenna such as a parabolic reflector, and mechanically moving it to point the beam, make use of many electrically small antennas (typically hundreds or thousands) and move the beam by varying the relative phasing of these antennas.