Methods of constructing optimum phased-array antennas for limited field of view

A survey is given of the methods of constructing phased-array antennas with optimum radiating structures that provide shaping of the flat-topped array-element patterns. This corresponds to maximization of the array gain in a given limited scanning sector, using a corresponding minimum number of controlled elements. The methods considered include the use of passive multiport networks, coupled dual-mode waveguides, protruding dielectric elements, corrugated structures, and quasi-optical networks that provide excitation of the necessary over-lapped subarrays.