Blade Antenna-SDR System Prototype for the CANTAR Global 21-cm Experiment: Simulations, Measurements, and In-Situ Results

TL;DR

This paper details the design, simulation, and initial testing of a low-frequency radio telescope prototype for 21-cm cosmology, combining a blade dipole antenna with SDR technology to achieve high sensitivity in remote sites.

Contribution

It introduces a novel low-frequency antenna-SDR system prototype tailored for 21-cm reionization experiments, including comprehensive simulations and in-situ measurements.

Findings

Simulations show favorable antenna impedance and beam properties.

SDR tests confirm system performance and low-noise amplification.

Radiometric estimates indicate potential for sub-mK sensitivity with sufficient integration.

Abstract

We present the design and initial testing of a low-frequency radio telescope prototype developed for the CANTAR (Colombian Antarctic Telescope for 21-cm Absorption during Reionization) experiment. Operating from 100 to 200 MHz, the system integrates a blade dipole antenna inspired by the EDGES high-band design with a software-defined radio (SDR) receiver. We report simulations of antenna impedance and beam chromaticity, along with SDR performance tests (Limenet Mini, Ettus E310, USRP2920). A dual-stage low-noise amplifier reduces system temperature, enabling foreground-sensitive observations. Radiometric estimates suggest sub-mK sensitivity is achievable with 1000 h of integration. This prototype forms part of Colombia's emerging infrastructure for 21-cm cosmology, with deployments planned in low-RFI sites in the Colombian Andes and Antarctica.