| 26th of February 2015 |
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| ASKAP Highlights - Mk II Phased-Array Feed |
| by Aaron Chippendale (CASS) |
| This is the first Mk II phased-array feed
(PAF), which was installed on ASKAP antenna 29 in September 2014. The Mk II PAF
has
significantly improved astronomical performance compared to the Mk I. It
also employs new technologies to improve operability and
maintainability. Optical fibre transports all PAF signals to the central
signal processor, up to six kilometres away. Thermoelectric cooling maintains
a workable and stable temperature with just one moving part, a simple fan to
blow air over external heat exchangers. The outer case of the PAF is built
using marine composite technology to manage structural loading while
providing thermal insulation, environmental protection, and electromagnetic
shielding. See Hampson (2012) for a full description. Phased-array feeds allow radio telescope dishes to capture information from a larger area of sky in a single pointing. ASKAP PAFs capture information from a 30 deg2 field-of-view, around 20 times more sky than a traditional "single-pixel" feed would see on the same dish. CSIRO developed sensitive phased-array feeds for ASKAP that are dual-polarised, low-profile, and inherently wide-band. They are based on a connected-element "chequerboard" array (Hay and O'Sullivan 2008) and have won national awards for engineering excellence and innovation. |