A systematic approach to the design of a radiator element for a phased-array antenna

A planar phased-array antenna presents a reflection at its face which varies greatly with phasing for wide-angle steering of the beam. A radiator element for an array of many elements may be designed on the basis of an infinite array, simulated in waveguide for measurements or expressed in terms of the "grating-lobe series" for computation. Neither of these techniques is sufficient by itself, but the two are complementary to give the required information on array performance. There is presented a commentary on the problems peculiar to the design of a radiator element, followed by a description of some design techniques, and an outline of a design procedure based on these techniques. The validity and utility of this approach has been demonstrated in element designs for several arrays of many elements. A few examples are discussed. The practical benefit is the resulting economy of effort and lapsed time required to arrive at a proven design, based on simulator tests of a few elements and computations for a wide range of conditions.