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Cassegrain antenna

About: Cassegrain antenna is a research topic. Over the lifetime, 3207 publications have been published within this topic receiving 28278 citations.


Papers
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Proceedings ArticleDOI
21 Mar 1998
TL;DR: The use of inflatable structures in space has both fascinated and challenged many in the space community for forty years or more as discussed by the authors, and the evolution of precision inflatable reflector design from simpler inflatable structure that have flown in space.
Abstract: The use of inflatable structures in space has both fascinated and challenged many in the space community for forty years or more. The authors present some history on the evolution of precision inflatable reflector design from simpler inflatable structures that have flown in space. Examples of reflectors that have been ground tested are presented and discussed, followed by a description of the Inflatable Antenna Experiment off the Shuttle in 1996. Results from the surface accuracy measurements of some of these reflectors are also presented, along with measured and calculated RF gain and beam patterns of the 3-meter L'Garde Demonstrator Program (LDP) reflector. Finally, the authors comment on the current status of space inflatable reflector technology at L'Garde.

23 citations

Journal ArticleDOI
TL;DR: In this article, a broadband antenna with an elliptical beam suitable for efficient illumination of the United States from a satellite in synchronous orbit is described, which is also suitable for use in terrestrial radio systems above 10 GHz.
Abstract: A broadband antenna is described with an elliptical beam suitable for efficient illumination of the United States from a satellite in synchronous orbit. The antenna is also suitable for use in terrestrial radio systems above 10 GHz. It consists of a corrugated feed and two parabolic cylinders that efficiently transform the circularly symmetric beam radiated by the feed into an elliptical beam. Depolarization of the incident beam by the two cylinders is very small and essentially independent of the angle of incidence, which can therefore be chosen as large as required to avoid aperture blockage. The performance is described of an antenna with a 5.8° × 2.9° elliptical beam at 18.5 GHz. For any input polarization, the cross-polarized component of the far field remains over the entire beam at least 33.5 dB below the main component on axis. This cross-polarized component is due in part to imperfections in the corrugated feed and in part to some aperture blockage by the feed and depolarization by the cylinders. A first-order analysis of the frequency dependence shows that the beamwidths vary little with frequency for an antenna using a properly designed feed and cylinders of sufficiently large apertures. As the frequency is increased from 18.5 to 29 GHz, the measured horizontal and vertical beamwidth variations are +1.7 and −14 percent, respectively.

23 citations

Journal ArticleDOI
TL;DR: In this paper, a shaped reflector antenna for a prototype 60 GHz wireless LAN access point has been designed and constructed, and its performance has been verified through measurements of the antenna far-field radiation patterns in the compact antenna test range.
Abstract: A shaped reflector antenna for a prototype 60-GHz wireless LAN access point has been designed and constructed. Its performance has been verified through measurements of the antenna far-field radiation patterns in the compact antenna test range. Near-field patterns have been reconstructed from the measured far-field data by using the Hankel transform. The results show that the amplitude across the footprint area remains within 6 dB of uniformity.

23 citations

Journal ArticleDOI
TL;DR: In this article, it is shown that the separation of the co-and cross-polar components of the primary field does not depend on the symmetry of the antenna, and that it holds even for off-set fed reflectors.
Abstract: It is well known that focussed, axial symmetrical reflector antennas collimate the co- and cross-polar components of the primary field separately, i.e., the reflector does not create a contribution to the cross polarization of the far-field. By a simple extension of a classical physical argument it is demonstrated that this separability does not depend on the symmetry of the antenna, and that it, therefore, holds even for off-set fed reflectors. A new mathematical formulation of the collimation is derived in which this is shown. Yet the separability does depend on how the co- and cross-polar fields are defined, and the cross polarization of feeds for asymmetric reflectors is discussed in detail in the light of this. It is further suggested how to design low cross polarization feeds for off-set fed antennas. As a consequence of the separate collimation such feeds will lead to low cross-polarization of the secondary fields. Two simple examples are treated. The only limitations of the results are those due to the application of the aperture field version of the physical optics approximation.

23 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202318
202267
202111
202018
201920
201824