Following the reported detection of an absorption profile associated with the 21~cm sky-averaged signal from the Cosmic Dawn by the EDGES experiment in 2018, a number of experiments have been set up to verify this result. This paper discusses the design process used for global 21~cm experiments, focusing specifically on the Radio Experiment for the Analysis of Cosmic Hydrogen (REACH). This experiment will seek to understand and compensate for systematic errors present using detailed modelling and characterization of the instrumentation. There is detailed the quantitative figures of merit and numerical modelling used to assist the design process of the REACH dipole antenna (one of the 2 antenna designs for REACH Phase I). This design process produced a 2.5:1 frequency bandwidth dipole. The aim of this design was to balance spectral smoothness and low impedance reflections with the ability to describe and understand the antenna response to the sky signal to inform the critically important calibration during observation and data analysis.
@article{arxiv.2109.10098,
title = {Radio antenna design for sky-averaged 21 cm cosmology experiments: the REACH case},
author = {J. Cumner and E. De Lera Acedo and D. I. L. de Villiers and D. Anstey and C. I. Kolitsidas and B. Gurdon and N. Fagnoni and P. Alexander and G. Bernardi and H. T. J. Bevins and S. Carey and J. Cavillot and R. Chiello and C. Craeye and W. Croukamp and J. A. Ely and A. Fialkov and T. Gessey-Jones and Q. Gueuning and W. Handley and R. Hills and A. T. Josaitis and G. Kulkarni and A. Magro and R. Maiolino and P. D. Meerburg and S. Mittal and J. R. Pritchard and E. Puchwein and N. Razavi-Ghods and I. L. V. Roque and A. Saxena and K. H. Scheutwinkel and E. Shen and P. H. Sims and O. Smirnov and M. Spinelli and K. Zarb-Adami},
journal= {arXiv preprint arXiv:2109.10098},
year = {2023}
}
Comments
32 pages, 30 figures, to be submitted to the Journal of Astronomical Instrumentation