Ultrawideband Conical Log-Spiral Circularly Polarized Feed for Radio Astronomy Articles uri icon

publication date

  • March 2020

start page

  • 1995

end page

  • 2007

issue

  • 3

volume

  • 68

International Standard Serial Number (ISSN)

  • 0018-926X

Electronic International Standard Serial Number (EISSN)

  • 1558-2221

abstract

  • In order to meet the requirements of the new generation of radio telescopes, we have developed a new topology called DYQSA, which stands for DYson Quad-Spiral Array. The design exhibits dual circular polarization contrary to dual linear polarization of state-of-the-art feeds. It covers the required ultrawideband (UWB) from 2 to 14 GHz with an almost constant and real input impedance which facilitates the design of the feeding structure and the low-noise amplifiers (LNAs). Different versions are investigated for enhancing feed performance, ensuring higher aperture efficiencies and mechanical stability. The simulation results of the reflector loaded by the proposed feed show an aperture efficiency of 65%±5% with a noise antenna temperature around 14 K and a system equivalent flux density (SEFD) of about 1300 Jy, both averaged over the required bandwidth at zenith. Measurements of the single-element and the four-element feeds are presented. Comparisons with other state-of-the-art feeds are shown in terms of total aperture efficiencies, design adaptability to different reflectors, calibration signal injection, and the required number of LNAs per feed, cost, and physical volume.

subjects

  • Telecommunications

keywords

  • 3-d printing; circular polarization; conical antennas; dual-polarized antennas; dyson quad-spiral array (dyqsa); log spiral antennas; radio astronomy; radio telescopes; reflector antenna feeds; ultrawideband (uwb) antennas; very long baseline interferometry (vlbi); vlbi2010 global observing system (vgos)