Design of dual reflector antennas with arbitrary phase and amplitude distributions

Conventional dual reflector antenna systems have been based largely on the Cassegrain parabola-hyperbola design or the Gregorian parabola-ellipse design[1]. The designs are based on the principles of geometrical optics with consequent limitations. A generalization of the optical design is presented here which allows the synthesis of reflector shapes for arbitrary phase and amplitude distributions in the aperture of the larger reflector with an arbitrary primary feed. In contrast, a single reflector design permits either phase or amplitude control in the aperture. The analysis will be made for a surface of revolution and results presented for a uniform phase and amplitude case.