# Simulation and Testing of a Linear Array of Modified Four-Square Feed Antennas for the Tianlai Cylindrical Radio Telescope

## TL;DR

This paper presents the design, simulation, and experimental validation of a wideband, dual-polarized four-square antenna array used as a line-feed for the Tianlai cylindrical radio telescope, aimed at 21cm intensity mapping.

## Contribution

It introduces a modified four-square antenna design and evaluates its performance through simulations and experiments across a broad frequency range for radio astronomy.

## Key findings

- Beam pattern simulations match experimental results
- The antenna array performs effectively across 650-1420 MHz
- The design is suitable for 21cm intensity mapping applications

## Abstract

A wide bandwidth, dual polarized, modified four-square antenna is presented as a feed antenna for radio astronomical measurements. A linear array of these antennas is used as a line-feed for cylindrical reflectors for Tianlai, a radio interferometer designed for 21~cm intensity mapping. Simulations of the feed antenna beam patterns and scattering parameters are compared to experimental results at multiple frequencies across the 650 - 1420 MHz range. Simulations of the beam patterns of the combined feed array/reflector are presented as well.