A fundamental figure of merit for radio polarimeters

Carozzi, T.D. and Woan, G. (2011) A fundamental figure of merit for radio polarimeters. IEEE Transactions on Antennas and Propagation, 59(6), pp. 2058-2065. (doi:10.1109/TAP.2011.2123862)

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Publisher's URL: http://dx.doi.org/10.1109/TAP.2011.2123862

Abstract

Many modern radio applications, such as astronomy and remote sensing, require high-precision polarimetry. These ap- plications put exacting demands on radio polarimeters (antenna systemsthatcanmeasurethestateofpolarizationofradiosources), and in order to assess their polarimetric performance, a figure of merit (FoM) would be desirable. Unfortunately, we find that the parameter commonly used for this purpose, the cross-polarization ratio,isnotsuitableasapolarimetryFoMunlessitisgiveninanap- propriatecoordinatesystem.Thisisbecausealthoughthecross-po- larization ratio is relevant for raw, uncalibrated polarimetry, in general it is not relevant to the quality of the polarimetry after po- larimetric calibration. However, a cross-polarization ratio can be constructed from invariants of the Jones matrix (the matrix that describes the polarimetric response of a polarimeter) that quanti- fies polarimetric performance even after calibration. We call this cross-polarization ratio the intrinsic cross-polarization ratio (IXR) and conclude that it is a fundamental FoM for polarimeters. We thenextendtheIXRconceptfromtheJonescalculustotheMueller calculus and also to interferometers, and we give numerical exam- ples of these parameters applied to the Parkes radio telescope, the Westerbork synthesis radio telescope, and the Effelsbergtelescope. Index Terms—Instrumentation, polarimet

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Carozzi, Dr Tobia and Woan, Professor Graham
Authors: Carozzi, T.D., and Woan, G.
College/School:College of Science and Engineering > School of Physics and Astronomy
Journal Name:IEEE Transactions on Antennas and Propagation
ISSN:0018-926X

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
408312SKADS - Square Kilometre Array Design StudiesGraham WoanParticle Physics & Astronomy Research Council (PPARC)PP/E000266/1Physics and Astronomy