A concentric loop array

A circularly symmetric array has been developed which shows promise for general pattern synthesis and for electrical scanning. The basic elements of the array are thin wire concentric circular loops. A loop of circumference , n being an integer, carries a current standing wave which varies as , where is the angle of rotation about the axis of the loop. The radiation field in the plane of the loop has a dependence identical to that of the loop current. By properly exciting a pair of feeds on each of a number of loops it is possible to produce a desired radiation pattern or to rotate a beam in the coordinate. Off-axis radiation can be utilized or minimized, depending upon the application.