New technique for shaping axisymmetric dual-reflector antennas using conic sections to control aperture illumination

This work presents a new technique for the geometrical optics (GO) shaping of axisymmetric dual-reflector antennas. Both reflectors' generatrices are shaped by the continuous concatenation of conic sections, suited to provide simultaneous control of amplitude and phase of the aperture's GO field. With amplitude and phase control of the aperture field, the antenna designer has more options to achieve prescribed circularly symmetric radiation patterns. The GO formulation is derived for the well-known shaped Cassegrain configuration, but it can be easily adapted to other axisymmetric geometries. Illustrative GO designs are investigated and results validated by a full-wave analysis provided by the method of moments.