Antennas in Radio Telescope Systems

Abstract

Radio astronomy is the study of the universe by measurement of radio frequency emission at frequencies ranging from a few MHz to the far infrared. Signals of interest are typically extraordinarily weak, necessitating large effective aperture and resulting in some of the world's largest antenna systems. Technologies now commonly employed include reflector antennas ("dishes") using horn-type feeds or feed arrays, beamforming arrays consisting of elements ranging from dipoles to large dishes, and interferometry. Many problems in radio astronomy also require very fine angular resolution, leading to aperture synthesis imaging instruments consisting of antennas distributed over apertures ranging from hundreds of meters to intercontinental distances. This chapter provides a brief review of antenna systems used in operational modern radio telescopes and in anticipated new radio telescopes.

Weight Selection for Pattern Control of Paraboloidal Reflector Antennas with Reconfigurable Rim Scattering

“…As a result, the gain at ψ = 1.25 • is essentially zero. 3 This level of cancellation can be accomplished at any angle outside the main beam as shown in Figure 3. Specifically, in Figure 3 we plot the H-plane co-pol gain achieved at ψ (we will refer to this as G(ψ)) when the weights are generated using (9) to place a null at 1 • ≤ ψ ≤ 3 • (see plot labeled "optimal").…”

“…Radio astronomy is an example application that relies on large reflector antennas with high gain to receive weak signals [1]- [3]. However, with the high gains obtainable with large reflectors, these applications are still vulnerable to interference via sidelobes.…”

Sidelobe Modification for Reflector Antennas by Electronically-Reconfigurable Rim Scattering

“…An example is radio astronomy, where telescopes are commonly implemented as either large reflectors or arrays of large reflectors (see e.g., [3]). These systems are vulnerable to interference from satellite transmissions received through sidelobes.…”