Reflector Antenna Design Research Articles

Reviews and abstracts - Reflector antenna analysis and design

Reviews and abstracts - Reflector antenna analysis and design

Book reviews - Analysis of reflector antennas

The Analysis of the Reflector Antenna is a monograph which documents the recent advances in the theory of reflectors developed during the space program and particularly of the work at the Jet Propulsion Laboratory. It is written for the engineer who needs to understand the design and performance limitations of reflector antennas. While it is not a text book, it may also prove useful in engineering introduction courses on diffraction. The book is divided into three sections: 1) the mathematical theory of diffraction, 2) the definition and calculation of antenna parameters, and 3) the use of digital computers in the analysis and design of reflector antennas and feed systems.

Depolarization properties of offset reflector antennas

The cross polarized radiation for linearly polarized excitation and the beam displacement for circularly polarized excitation have been investigated for offset reflector antennas. Numerical calculations are given to illustrate the dependence upon the angle <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">\theta_{0}</tex> between the feed axis and the reflector axis as well as upon the half-angle <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">\theta_{c}</tex> subtended at the focus by the reflector. In the case <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">\theta_{0} = \theta_{c} = 45\deg</tex> , measured results have been obtained for both linearly and circularly polarized excitations with a dual mode feed illuminating an offset paraboloid. The cross polarized radiation of horn reflector and open Cassegrainian antennas rises sharply to rather high values off the beam axis; however, in general, the maximum cross polarized radiation of offset reflector antennas can be made small by using a small angle between the feed and reflector axes. The cross polarization caused by offset is compared with that caused by an unbalanced feed pattern. The effect of the longitudinal current distribution and of departure of the surface from a paraboloid on cross polarization are also examined. The clarification of these cross polarization properties is found to be valuable in the design of reflector antennas.

Parabolic Cylindrical Reflector Antennas

ABSTRACTThe characteristics of a parabolic cylindrical reflector antenna are discussed theoretically. It is assumed that the reflector surface has perfect conductivity and is fed by a line source which is placed at the focal line of the reflector. Theoretical expressions are given for the gain and aperture efficiency of the antenna in terms of the physical dimensions of the reflector and the feed. It is found that for a given pattern of the primary feed there exists an optimum size of the reflector so that the overall gain of the antenna is maximum. The gain of the antenna is discussed for different primary patterns. The effects of phase error and of the primary back lobe on the gain of the antenna are also discussed. The theoretical results given should be useful for the actual design of parabolic cylindrical reflector antennas.

A Limiting Case in the Design of an Excited Reflector Antenna

AbstractWith the increasing emphasis laid in this country at present on high power medium-wave broadcasting, preferably with directional antennae, a clear exposition of the problem of matching directional aerials was considered appropriate. The present article not merely brings together the basic theory relating to the excited reflector and the parasitic reflector, but spotlights the situation where the excited reflector breaks down. The vector diagrams help to comprehend clearly the role of the mutual impedance in altering the base impedance of the aerials to different values.