Phased Array Antennas

The theory of array antenna design has matured such that the tools are now available to design elements with predictable performance and to verify this performance with high confidence. The antenna feed is of equal importance to the antenna element. Multiple reflections in a poorly designed feed may generate spurious responses in the array antenna pattern. Space feeds offer economy and simplicity but tend to be limited in instantaneous bandwidth, flexibility of amplitude tapers, and ability to form clusters of beams. The near field off-set fed Gregorian reflector system appears to eliminate much of the inflexibility of the more conventional space-fed systems. This system is an attractive potential feed for the all-solid-state, phased-array radar. The all solid-state phased array radar typically will have a larger aperture relative to its vacuum tube counterpart. This large aperture increases the likelihood of the need for time-delay steering and clusters of simultaneous receive beams.