Complex source extension of UTD for analyzing large reflector antennas

A new uniform geometrical theory of diffraction for a fully three dimensional arbitrary curved wedge, when the illumination is an electromagnetic complex source beam is developed from the uniform asymptotic solution to appropriate canonical problems. This general development is then utilized for the analysis of large reflector antennas by expanding the reflector feed illumination in terms of a convergent complex source beam expansion. Each complex source beam in the expansion then reflects and diffracts from the metallic reflector via the uniform geometrical theory of edge diffraction for complex source beams. The field radiated by the reflector at any near or far zone observation point is given essentially in closed form via a superposition of the scattering of each complex source beam by the reflector. Only those complex source beams which strongly illuminate the reflector surface are retained. Moreover, for a given observation point only a few of those beams contribute significantly while others are ignorable, thus making this approach very efficient. The present method is more accurate than that which is commonly based on the time consuming numerical evaluation of the physical optics integral approximation for calculating the radiation fields of large reflector antennas.