Novel Beam-Scanning Center-Fed Imaging Reflector Antenna with Elliptical Aperture for Wide Area Observation

Michio TAKIKAWA  Yoshio INASAWA  Hiroaki MIYASHITA  Izuru NAITO  

Publication
IEICE TRANSACTIONS on Electronics   Vol.E99-C   No.9   pp.1031-1038
Publication Date: 2016/09/01
Online ISSN: 1745-1353
DOI: 10.1587/transele.E99.C.1031
Type of Manuscript: PAPER
Category: Electromagnetic Theory
Keyword: 
wide area observation,  elliptical aperture,  small observation satellite,  reflector antennas,  doubly curved reflector,  beam-scanning function,  center-fed reflector antenna,  

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Summary: 
We investigate a phased array-fed dual reflector antenna applying one-dimensional beam-scanning of the center-fed type, using an elliptical aperture to provide wide area observation. The distinguishing feature of this antenna is its elliptical aperture shape, in which the aperture diameter differs between the forward satellite direction and the cross-section orthogonal to it. The shape in the plane of the forward satellite direction, which does not have a beam-scanning function, is a ring-focus Cassegrain antenna, and the shape in the plane orthogonal to that, which does have a beam-scanning function, is an imaging reflector antenna. This paper describes issues which arose during design of the elliptical aperture shape and how they were solved, and presents design results using elliptical aperture dimensions of 1600 mm × 600 mm, in which the beam width differs by more than two times in the orthogonal cross-section. The effectiveness of the antenna was verified by fabricating a prototype antenna based on the design results. Measurement results confirmed that an aperture efficiency of 50% or more could be achieved, and that a different beam width was obtained in the orthogonal plane in accordance with design values.