COMPUTATION OF INDUCED SURFACE CURRENT OF THE MAIN REFLECTOR OF A SHAPED DUAL-REFLECTOR ANTENNA.

We describe a numerical procedure which combines the features of beam launching, organized search for reflection points by a scanning scheme, and the classical ray tracing. This numerical procedure is augmented by the inclusion of the edge diffraction effect which is computed by a new formula. The diffraction fields computed with this formula are compared with those derived from other uniform theories. The present method for edge calculation not only has certain advantages over the other uniform methods, but also is well-suited for current computations on the main reflector when the subreflector is specified only numerically, i. e. , both the surface and the rim of the subreflector are specified by coordinates and surface normals at discrete points.