[asac] [almanews] ALMA Memo No. 353 Released

[Carolyn White]

ALMA Memo No.353

Investigation of suppression of sidelobes by simple displacement of
clustered groups of regularly spaced antennas

Steven Heddle

March 2001

A means of suppressing beam sidelobes by simple displacements of subgroups
of regularly spaced antennas is proposed and investigated. Previous
experiments in the optical domain suggest that this should be possible,
and the principle is developed first by analogy and then by a simple
analysis to encompass the radio astronomical situation. Considering the
specific example of a hexagonal array with the additional constraint of
compactness, some improvement over a completely regularly placed
configuration is demonstrated. An analysis suggests why the improvement is
less than that hoped for. Alternative optimization methods yield compact
arrays with lower sidelobes, but the principle outlined here may prove
useful in other configurations.

View a PDF version of ALMA Memo #353.
     http://www.alma.nrao.edu/memos/html-memos/alma353/memo353.pdf

Download a postscript version of ALMA Memo #353.
     http://www.alma.nrao.edu/memos/html-memos/alma353/memo353.ps

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