Radio Interferometer with Simple antennas

TL;DR

This paper explores the use of simple antennas like dipoles, loops, or Yagi-UDA as elements in radio interferometers, deriving the mathematical relationship between antenna gain and visibility to aid in designing cost-effective arrays.

Contribution

It provides a detailed derivation from basic principles to relate antenna gain with interferometric visibility, enabling the design of simpler, more accessible radio interferometers.

Findings

Visibility decreases with lower antenna gain

Derived mathematical model from Young's double slit experiment

Practical guidance for designing simple antenna interferometers

Abstract

A Radio interferometer comprises several antennas, spared over a large area. Say ALMA(Atacama Large Millimeter/submillimeter Array), VLA(very large array), VLBA(Very Long Baseline Array), GMRT(Giant Metrewave Radio Telescope), MWA( Murchison Widefield Array), EHT(Event Horizon Telescope), and the SKA(Square Kilometer Array), the name itself speaks about square-kilometres of area. Most radio observatories are constructed or constitute giant dish antennas, and few constitute an extensive array of antennas. However, what if a simple antenna like Dipole, Loop or Yagi-UDA is considered an element of an interferometer? Then how does it affect the visibility of the instrument? Yes, it will be less, but how weak? Furthermore, what is the math to reach it? These questions pushed for this work. Here, one can find the detailed derivation starting from a simple Young's double slit experiment to a radio interferometer intensity distribution in terms of the Gain of the antenna element. This literature aided in understanding the interferometer of yagi antennas of Gain 11dBi, resulting in a visibility of 0.0714. This clarity was insignificant in the current work. Hence using this work, one can design and construct a suited interferometer for their requirement.