Sat, 26 Jul 2008 06:08:29 BST CiteULike: dcastro's cassegrain http://www.citeulike.org/user/dcastro/tag/cassegrain CiteULike.org en-gb Copyright © 2004-2008 citeulike.org http://www.citeulike.org/user/dcastro/article/2421499 <i>Antennas and Propagation, IEEE Transactions on [legacy, pre - 1988], Vol. 9, No. 2. (1961), pp. 140-153.</i><br /><br />A microwave antenna can be designed in the form of two reflecting dishes and a feed, based on the principle of the Cassegrain optical telescope. There are a variety of shapes and sizes available, all described by the same set of equations. The essential performance of a Cassegrain double-reflector system may be easily analyzed by means of the equivalent-parabola single-reflector concept. Techniques are available for reducing the aperture blocking by the sub dish of the Cassegraln system: one method minimizes the blocking by optimizing the geometry of the feed and sub dish; other methods avoid the blocking by means of polarization-twisting schemes. The former method yields good performance in a simple Cassegrain antenna when the beamwidth is about<tex>1deg</tex>or less. The latter methods are available for any application not requiring polarization diversity, and an optimized set of polarization-operative surfaces has been developed for these twisting Cassegrain antennas. Experimental results, presented for practical antennas of both types, illustrate the feasibility of these principles. A number of unusual benefits have been obtained in the various Cassegrain antenna designs, and additional interesting features remain to be exploited. Microwave antennas derived from the cassegrain telescope P Hannan Antennas and Propagation, IEEE Transactions on [legacy, pre - 1988], Vol. 9, No. 2. (1961), pp. 140-153. 2008-02-24T13:37:07-00:00 1961 Antennas and Propagation, IEEE Transactions on [legacy, pre - 1988] 9 2 140 153 antennas cassegrain microwave