A transformation between the phasing techniques required for linear and circular aerial arrays

The paper describes a method for producing an angular deflection, or continuous rotation, of any directional pattern formed from a circular (or cylindrical) array, by means of a simple linear progressive phase shift across the input ports of a multiple-port matrix network, whose output ports feed the array elements. If the progresive phase shift has a value of φ radians between adjacent ports, the directional pattern is rotated through an angle of φ radians. The principal advantage of the technique is that it enables any aperture distribution of a circular array to be electronically rotated by the simple phasing techniques normally associated with a linear array. It is also shown that the matrix network may take the form of a Butler-type matrix, which may be easily realised using only hybrid networks and phase shifters.