Journal ArticleDOI
Beam squint in axially symmetric reflector antennas with laterally displaced feeds
TLDR
In this article, the beam squint for circular polarized excitation has been measured using a 100 m telescope, where the feed horn was laterally displaced by 1.364 m from the optical axis at the system focus.Abstract:
Numerical calculations have been carried out and the beam squint for circular polarized excitation has been measured using a 100 m telescope. The telescope was operated in the Gregorian mode, where the equivalent focal length equals 387.5 m. The feed horn was laterally displaced by 1.364 m from the optical axis at the system focus. Good agreement was obtained between the numerical calculations and the experimental results. The authors found a shift of the two radiation patterns of approximately=2 arcsec. The orientation of the beam squint in the configuration with a laterally displaced feed is different from the orientation in offset reflector antennas. >read more
Citations
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Journal ArticleDOI
Beam squint determination in conic-section reflector antennas with circularly polarized feeds
Dah-Weih Duan,Yahya Rahmat-Samii +1 more
TL;DR: In this article, the beam squint phenomenon in circular-polarized-feed paraboloidal, Cassegrain, and Gregorian antennas is characterized and the geometrical optics/aperture field method is used to derive generalized squint-predicting formulas, which are verified by computer simulations based on diffraction analysis.
Posted Content
The Measurement of Polarization in Radio Astronomy
Timothy Robishaw,Carl Heiles +1 more
TL;DR: The measurement and calibration process for polarization observations is described and how instrumental polarization can affect a measurement is illustrated to draw attention to the confusion generated by various polarization conventions.
Journal ArticleDOI
Polarization properties of offset dual-reflector antennas
TL;DR: In this paper, the diffraction-induced cross polarizations calculated from the differential phase shift between the fundamental TEM/sub 00/ and higher order TEM /sub 01/ Gaussian beam modes, which represent principal and cross-polarization components, respectively, are in agreement with measured data.
Journal ArticleDOI
Design and development of a conjugate matched feed for an offset parabolic reflector antenna
TL;DR: In this article, a tri-mode conjugate matched feed was proposed to suppress the unwanted high cross-polarization and beam squinting in an offset parabolic reflector antenna.
Book ChapterDOI
1. Antenna Basics
Luigi Boccia,Olav Breinbjerg +1 more
Abstract: Antennas radiate and receive electromagnetic waves by converting guided waves supported by a guiding structure into radiating waves propagating in free space and vice versa. This function has to be accomplished by fulfilling specific requirements which affect the antenna design in different ways. In general, a number of antennas are installed in a satellite and their requirements vary depending on the application and on the mission. They can be roughly classified into three types: antennas for telemetry, tracking and control (TT&C), high-capacity antennas, and antennas for space instruments or for other specific applications. Several examples of the latter class are reported in the third section of this book. This chapter provides an overview of the basic antenna parameters and antenna types, and it presents other basic concepts related to the space environmentwhichwill introduce the reader to the development of antennas for space applications. Although many basic definitions are presented, the chapter is not intended to provide a comprehensive background to antennas. For this reason, the reader should refer to the extensive literature available on the subject, some of which we list as references. The chapter is organized as follows. In the first part, the main antenna parameters will be given in accordance with the IEEE Standard Definition of Terms for Antennas [1] and with the IEEE Standard Test Procedures for Antennas [2] which will be adopted throughout the book. In the second part of the chapter, basic antenna types commonly employed in spaceborne applications will be presented. In the third part of the chapter, antenna development will be related to the space environment by introducing fundamental concepts such as multipaction and outgassing.
References
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Journal ArticleDOI
A uniform geometrical theory of diffraction for an edge in a perfectly conducting surface
R.G. Kouyoumjian,P.H. Pathak +1 more
TL;DR: In this article, a compact dyadic diffraction coefficient for electromagnetic waves obliquely incident on a curved edse formed by perfectly conducting curved plane surfaces is obtained, which is based on Keller's method of the canonical problem, which in this case is the perfectly conducting wedge illuminated by cylindrical, conical, and spherical waves.
Journal ArticleDOI
Lateral-feed displacement in a paraboloid
TL;DR: In this article, the beam shift and degradation of a paraboloidal reflector with an offset feed is analyzed by the scalar plane wave theory, and the beam characteristics for a tapered circularly symmetric illumination are presented.
Journal ArticleDOI
Depolarization properties of offset reflector antennas
TL;DR: In this paper, the cross-polarity of offset reflector antennas was investigated for linearly and circularly polarized excitations with a dual mode feed illuminating an offset paraboloid.
Book
Analysis of reflector antennas
P. D. Patter,W. V. T. Rusch +1 more
TL;DR: In this paper, the authors present an analysis of reflector antennas covering electromagnetic field equations, computer aided design, and computer-aided design of reflectors for reflector antenna arrays.