Spectral performance of SKA Log-periodic Antennas I: mitigating spectral artefacts in SKA1-LOW 21 cm cosmology experiments
Date Issued
2017
Author(s)
de Lera Acedo, Eloy
•
Trott, Cathryn M.
•
Wayth, Randall B.
•
Fagnoni, Nicolas
•
•
Wakley, Brett
•
Koopmans, Léon V.E.
•
Faulkner, Andrew J.
•
bij de Vaate, Jan Geralt
Abstract
This paper is the first in a series of papers describing the impact of antenna instrumental artefacts on the 21 cm cosmology experiments to be carried out by the low frequency instrument (SKA1-LOW) of the Square Kilometre Array telescope (SKA), I.e. the Cosmic Dawn (CD) and the Epoch of Reionization (EoR). The smoothness of the passband response of the current log-periodic antenna being developed for the SKA1-LOW is analysed using numerical electromagnetic simulations. The amplitude variations over the frequency range are characterized using low-order polynomials defined locally, in order to study the impact of the passband smoothness in the instrument calibration and CD/EoR Science. A solution is offered to correct a fast ripple found at 60 MHz during a test campaign at the SKA site at the Murchison Radio-astronomy Observatory, Western Australia in 2015 September with a minor impact on the telescope's performance and design. A comparison with the Hydrogen Epoch of Reionization Array antenna is also shown demonstrating the potential use of the SKA1-LOW antenna for the delay-spectrum technique to detect the EoR.
Volume
469
Issue
3
Start page
2662
Issn Identifier
0035-8711
Ads BibCode
2017MNRAS.469.2662D
Rights
open.access
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