Spectral performance of SKA Log-periodic Antennas I: Mitigating spectral artefacts in SKA1-LOW 21-cm cosmology experiments

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 analyzed 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 September 2015 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.

arXiv comment11 pages, 12 figures, accepted for publication (MNRAS)

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Cited by in corpus (11)

• Deep multi-redshift limits on Epoch of Reionisation 21cm Power Spectra from Four Seasons of Murchison Widefield Array Observations
• Fundamental Limitations on the Calibration of Redundant 21 cm Cosmology Instruments and Implications for HERA and the SKA
• What is the SKA-Low Sensitivity for Your Favourite Radio Source ?
• Observing the Reionization : Effect of Calibration and Position Errors on Realistic Observation Conditions
• Antenna design for the SKA1-LOW and HERA super radio telescopes
• Accuracy vs. Complexity: Calibrating radio interferometer arrays with non-homogeneous element patterns
• Ionospheric effect on the synthetic Epoch of Reionization observations with the SKA1-Low
• Synthetic Observations with the Square Kilometre Array (SKA) -- development towards an end-to-end pipeline
• Impact of Calibration and Position Errors on Astrophysical Parameters of the HI 21cm Signal
• The Aperture Array Verification System 1: System overview and early commissioning results
• Mitigating gain calibration errors from EoR observations with SKA1-Low AA*