NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Array feed synthesis for correction of reflector distortion and Vernier beamsteeringAn algorithmic procedure for the synthesis of planar array feeds for paraboloidal reflectors is described which simultaneously provides electronic correction of systematic reflector surface distortions as well as a Vernier electronic beamsteering capability. Simple rules of thumb for the optimum chioce of planar array feed configuration (i.e., the number and type of elements) are derived from a parametric study made using the synthesis procedure. A number of f/D ratios and distortion models were examined that are typical of large paraboloidal reflectors. Numerical results are presented showing that, for the range of distortion models considered, good on-axis gain restoration can be achieved with as few as seven elements. For beamsteering to +/- 1 beamwidth (BW), 19 elements are required. For arrays with either 7 or 19 elements, the results indicate that the use of high-aperture-efficiency elements (e.g., disk-on-rod and short backfire) in the array yields higher system gain than can be obtained with elements having lower aperture efficiency (e.g., open-ended waveguides). With 37 elements, excellent gain and beamsteering performance to +/- 1.5 BW are obtained independent of the assumed effective aperture of the array element. An approximate expression is derived for the focal-plane field distribution of the distorted reflector. Contour plots of the focal-plane fields are also presented for various distortion and beam scan angle cases. The results obtained show the effectiveness of the array feed approach.
Document ID
19890033855
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Blank, Stephen J.
(New York Institute of Technology Old Westbury, United States)
Imbriale, William A.
(California Institute of Technology Jet Propulsion Laboratory, Pasadena, United States)
Date Acquired
August 14, 2013
Publication Date
October 1, 1988
Publication Information
Publication: IEEE Transactions on Antennas and Propagation
Volume: 36
ISSN: 0018-926X
Subject Category
Communications And Radar
Accession Number
89A21226
Distribution Limits
Public
Copyright
Other

Available Downloads

There are no available downloads for this record.
No Preview Available