Prediction of aperture efficiency ripple in clear aperture offset Gregorian antennas

Date
2013
Journal Title
Journal ISSN
Volume Title
Publisher
Institute of Electrical and Electronics Engineers
Abstract
ENGLISH ABSTRACT: Electrically small clear aperture dual offset reflector systems often exhibit a directivity ripple over frequency due to the interference of the diffracted field from the sub-reflector with the main beam field. This paper investigates the cause of the ripple, and presents a technique to predict the expected system directivity, including the ripple, using the feed radiation pattern augmented by an efficient simulation strategy in a clear aperture offset Gregorian system. The method allows for accurate prediction of the directivity ripple using a severely under-sampled set of simulation results. Predicted results are compared to several simulations, and agreement to better than 0.5 % is found for the majority of configurations using both analytical and full wave simulated feed patterns.
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Description
CITATION: De Villiers, D. I. L. 2013. Prediction of aperture efficiency ripple in clear aperture offset Gregorian antennas. IEEE Transactions on Antennas and Propagation, 61(5):2457-2465, doi: 10.1109/TAP.2013.2239953.
The original publication is available at http://ieeexplore.ieee.org
Keywords
Diffraction, Radio astronomy, Aperture efficiency, Reflector antennas
Citation
De Villiers, D. I. L. 2013. Prediction of aperture efficiency ripple in clear aperture offset Gregorian antennas. IEEE Transactions on Antennas and Propagation, 61(5):2457-2465, doi: 10.1109/TAP.2013.2239953