A concentric loop array

Abstract

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 circumferencen\lambda, n being an integer, carries a current standing wave which varies as\cos n \phi, where\phiis the angle of rotation about the axis of the loop. The radiation field in the plane of the loop has a\phidependence 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\phicoordinate. Off-axis radiation can be utilized or minimized, depending upon the application.