Antenna Design and Implementation for the Future Space Ultra-Long Wavelength Radio Telescope

TL;DR

This paper proposes a space-based ultra-long wavelength radio antenna system, including a tripole antenna and low-power receiver, optimized for celestial noise levels in the 1-30 MHz range, to enable ULW radio astronomy beyond Earth's ionosphere.

Contribution

It introduces a novel antenna design and system architecture specifically tailored for space ULW radio astronomy, addressing ionospheric and interference challenges.

Findings

Prototype tripole antenna meets noise temperature requirements.

System analysis indicates feasibility for space ULW array deployment.

Field experiments validate antenna performance in target frequency band.

Abstract

In radio astronomy, the Ultra-Long Wavelengths (ULW) regime of longer than 10 m (frequencies below 30 MHz), remains the last virtually unexplored window of the celestial electromagnetic spectrum. The strength of the science case for extending radio astronomy into the ULW window is growing. However, the opaqueness of the Earth's ionosphere makes ULW observations by ground-based facilities practically impossible. Furthermore, the ULW spectrum is full of anthropogenic radio frequency interference (RFI). The only radical solution for both problems is in placing an ULW astronomy facility in space. We present a concept of a key element of a space-borne ULW array facility, an antenna that addresses radio astronomical specifications. A tripole-type antenna and amplifier are analysed as a solution for ULW implementation. A receiver system with a low power dissipation is discussed as well. The active antenna is optimized to operate at the noise level defined by the celestial emission in the frequency band 1 - 30 MHz. Field experiments with a prototype tripole antenna enabled estimates of the system noise temperature. They indicated that the proposed concept meets the requirements of a space-borne ULW array facility.