A GTD analysis of the far-out sidelobes of cassegrain antennas

Using recent developments of the geometrical theory of diffraction (GTD), the complete
E
- and
H
-plane patterns of Cassegrain antennas are computed. The pattern in the main beam region is computed by conventional aperture integration methods and the GTD analysis is used to evaluate the far-out lobes caused by spillover and by various edge diffraction processes. The effects of the edge curvature and surface curvature are included in the computations.