Phased Array

Phased array feeds for radio astronomy

We’ve developed a specialised ‘camera’ for our newest radio telescope that dramatically increases how quickly it can survey the sky, and offers enormous potential for other rapid-imaging applications.

THE CHALLENGE

Speeding up radio astronomy
Radio telescopes use specialised cameras, called receivers, to detect and amplify faint radio waves from space. Most of these cameras only see a small part of the sky at once, which makes surveying large parts of the sky a time-consuming process.

For more than a decade we’ve been developing receivers with a larger field-of-view, and these have been used on our own Parkes radio telescope as well as other world-leading instruments.

OUR RESPONSE

Phased array feeds – a radical new approach to radio astronomy
For our newest radio telescope, the Australian Square Kilometre Array Pathfinder – ASKAP, we’ve developed innovative ‘phased array feed’ receivers with a wide field-of-view. This is the first time that this type of technology has been used in radio astronomy.

https://www.youtube.com/watch?v=lfXIuP9ST4w

Each phased array feed is made up of 188 individual receivers, positioned in a chequerboard-like arrangement. Alongside the receivers are low-noise amplifiers, which greatly enhance the weak radio wave signals received. These components are housed in a water-tight case mounted at the focal point above each of ASKAP’s antennas. Together with specialised digital systems developed for ASKAP, the phased array feeds create 36 separate (simultaneous) beams to give a field-of-view of 30 square degrees on the sky.

This pioneering technology will make ASKAP the fastest radio telescope in the world for surveying the sky, taking panoramic snapshots over 100 times the size of the full Moon.

First-generation phased array feeds have already been fitted to six of ASKAP’S 36 antennas and the early science results are outstanding. Second-generation phased array feeds, the result of a program to streamline their manufacture and make operational enhancements, are in the final stages of development and testing before full-scale production begins.

Along with colleagues in The Netherlands, Canada and the USA we’re also developing phased array feeds as rapid-imaging devices for potential use by the much larger Square Kilometre Array telescope, and for wider use throughout the world’s leading radio-astronomy observatories.

Phased array feed technology also has enormous potential outside astronomy. Much like our fast wireless LAN technology (which was developed from our expertise in radio astronomy and led to ‘WiFi’, the way most of us now access the internet without wires), phased array feeds could make a positive impact in a variety of alternative applications. For example, geophysics and medical physics could benefit from the rapid imaging made possible by phased array feeds.

Recognition of our phased array feed technology is building: it won Engineers Australia’s national Engineering Excellence Award in 2013, and was overall winner in The Australian Innovation Challenge in 2014.