A collective uniform geometrical theory of diffraction ray field analysis of very long and narrow finite planar arrays

An analytical development is presented for efficiently describing the electromagnetic (EM) fields radiated by very long but narrow finite rectangular planar arrays, which radiate in the presence of a planar perfectly conducting surface of infinite or large finite extent. A uniform geometrical theory of diffraction (UTD) solution is obtained which expresses, in a collective fashion, the fields emanating from each row of the antenna array elements, which propagate along three basic rays, namely one from each of the two ends of each row, and one from within the interior point on each row. Such a row by row field summation based description greatly simplifies the solution in contrast to conventional array element by element field summation method. Furthermore, this collective UTD ray field description provides a simple physical picture for array radiation mechanisms, which is generally absent in other methods of solution. The application of this work is to the rapid analysis of electronically scanned, very long, but narrow arrays which can produce an extremely sharp beam in the plane confining the array axis (along the long array dimension) and the normal to the array face.