Analysis of Electrically Small Hyperbolic Subreflectors Utilizing the Geometrical Theory of Diffraction
Cassegrain antennas have been utilized in applications where small size is critical. It has been observed that for antennas having subreflectors on the order of only several wavelengths in diameter, near-in sidelobe levels rise beyond normally predicted values. E-plane sidelobes are often several dB higher than those in the H-plane. Disturbances in the illumination of the primary reflector due to diffraction limitations of the electrically small subreflector are a possible cause of the sidelobe phenomenon. This thesis reports the results of a geometrical theory of diffraction analysis of the scattering from three to eight wavelength diameter hyperboloidal subreflectors based on the uniform geometrical theory of diffraction for curved edges in curved screens. The results are compared to physical optics solutions. Degradation of the scatter patterns are observed as subreflector size is decreased, and differences in the E- and H- plane phase and amplitude patterns are observed in the geometrical theory of diffraction solution.
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Master of Science (M.S.)
College of Engineering
Electrical Engineering and Communication Sciences
Length of Campus-only Access
Masters Thesis (Open Access)
Dissertations, Academic -- Engineering; Engineering -- Dissertations, Academic
Cook, David C., "Analysis of Electrically Small Hyperbolic Subreflectors Utilizing the Geometrical Theory of Diffraction" (1990). Retrospective Theses and Dissertations. 3964.