학술논문

Radio antenna design for sky-averaged 21 cm cosmology experiments: the REACH case
Document Type
Working Paper
Source
Subject
Astrophysics - Instrumentation and Methods for Astrophysics
Astrophysics - Cosmology and Nongalactic Astrophysics
Language
Abstract
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.
Comment: 32 pages, 30 figures, to be submitted to the Journal of Astronomical Instrumentation