Broad-band, high-gain, low-frequency Antennas for Radio Detection of Earth-skimming Tau Neutrinos

TL;DR

This paper explores the design of broad-band, high-gain, low-frequency antennas, specifically the 'rhombus' design, optimized for detecting radio signals from Earth-skimming tau neutrinos in the atmosphere.

Contribution

It introduces a novel antenna design suitable for high-gain, broad-band, low-frequency applications in neutrino detection, emphasizing mechanical simplicity and ground insensitivity.

Findings

The 'rhombus' antenna provides high gain and smooth beam patterns.

Design is insensitive to ground conditions and easily impedance-matched.

Suitable for deployment in inaccessible terrains for neutrino detection.

Abstract

A promising approach to detect high-energy tau neutrinos is through the measurement of impulsive radio emission from horizontal air showers initiated in the Earth's atmosphere. Observations at frequencies between 30 and 80 MHz seem particularly promising -- if high-gain antennas focused at the horizon and blocking out as much as possible of the noisy sky are employed. Due to the large wavelengths, however, designing an antenna with the required properties is highly non-trivial at such low frequencies. In this article, we explore suitable antenna designs that provide the desired high gain, possess a smooth beam, are insensitive to ground conditions, are easily impedance-matched over the wide band, and are mechanically simple for deployment in large numbers in inaccessible terrain. In particular, we consider the "rhombus" antenna design for both horizontally and vertically polarized radiation a very attractive option for tau neutrino detection efforts in the atmosphere with the radio technique.