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dc.contributor.authorSutinjo, Adrian
dc.contributor.authorO'Sullivan, J.
dc.contributor.authorLenc, E.
dc.contributor.authorWayth, Randall
dc.contributor.authorPadhi, S.
dc.contributor.authorHall, Peter
dc.contributor.authorTingay, Steven
dc.date.accessioned2018-01-30T08:00:10Z
dc.date.available2018-01-30T08:00:10Z
dc.date.created2018-01-30T05:59:02Z
dc.date.issued2015
dc.identifier.citationSutinjo, A. and O'Sullivan, J. and Lenc, E. and Wayth, R. and Padhi, S. and Hall, P. and Tingay, S. 2015. Understanding instrumental Stokes leakage in Murchison Widefield Array polarimetry. Radio Science. 50 (1): pp. 52-65.
dc.identifier.urihttp://hdl.handle.net/20.500.11937/60364
dc.identifier.doi10.1002/2014RS005517
dc.description.abstract

This paper offers an electromagnetic, more specifically array theory, perspective on understanding strong instrumental polarization effects for planar low-frequency "aperture arrays" with the Murchison Widefield Array (MWA) as an example. A long-standing issue that has been seen here is significant instrumental Stokes leakage after calibration, particularly in Stokes Q at high frequencies. A simple model that accounts for interelement mutual coupling is presented which explains the prominence of Q leakage seen when the array is scanned away from zenith in the principal planes. On these planes, the model predicts current imbalance in the X (E-W) and Y (N-S) dipoles and hence the Q leakage. Although helpful in concept, we find that this model is inadequate to explain the full details of the observation data. This finding motivates further experimentation with more rigorous models that account for both mutual coupling and embedded element patterns. Two more rigorous models are discussed: the "full" and "average" embedded element patterns. The viability of the full model is demonstrated by simulating current MWA practice of using a Hertzian dipole model as a Jones matrix estimate. We find that these results replicate the observed Q leakage to approximately 2 to 5%. Finally, we offer more direct indication for the level of improvement expected from upgrading the Jones matrix estimate with more rigorous models. Using the average embedded pattern as an estimate for the full model, we find that Q leakage of a few percent is achievable.

dc.publisherBlackwell Publishing Ltd
dc.titleUnderstanding instrumental Stokes leakage in Murchison Widefield Array polarimetry
dc.typeJournal Article
dcterms.source.issn0048-6604
dcterms.source.titleRadio Science
curtin.note

This is the peer reviewed version of the following article: Sutinjo, A. and O'Sullivan, J. and Lenc, E. and Wayth, R. and Padhi, S. and Hall, P. and Tingay, S. 2015. Understanding instrumental Stokes leakage in Murchison Widefield Array polarimetry. Radio Science. 50 (1): pp. 52-65, which has been published in final form at 10.1002/2014RS005517. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving at http://olabout.wiley.com/WileyCDA/Section/id-828039.html

curtin.departmentDepartment of Electrical and Computer Engineering
curtin.accessStatusOpen access


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