10:00am – 11:00am
UC San Diego // Jacobs Hall // 4th Floor // Room 4309
“Low-frequency” for radio astronomers is “Very HighFrequency” (VHF) for electrical engineers, i.e. up to ~300MHz. It is considered “low frequency” because it is lower than the typical operating frequency of a dish antenna. Similarly, “aperture arrays” do not involve any apertures (i.e. holes), but rather they are so named to distinguish them from dish arrays. In truth, “aperture arrays” often take the form of “wire antenna arrays” as we expect to find in the VHF range. Hence, for the electrical engineers, it is now clear that the topic of this talk is VHF wire antenna array engineering for radio astronomy in Western Australia. I will touch on a couple of topics relating to Low-Frequency Aperture Array (LFAA) engineeringactivities at Curtin University. The first is verification and test of an engineering prototype array of log-periodic antennas (the type being considered for Low-Frequency Square Kilometre Array, SKA-Low). I will present an in-situ radio interferometry based antenna measurement for this array. The second topic is regarding our effort to understand and model instrumental polarization effects of LFAA including the Murchison Widefield Array (MWA). Unlike dish observations, source tracking in LFAA is done by electronic scanning as opposed to mechanical means. This leads to strong instrumental polarization that must be well understood and calibrated. I will present a phased array theory perspective on this and discuss a modelling approach to account for this effect.
Adrian Sutinjo is a Senior Lecturer in Electrical and Computer Engineering at Curtin University in Western Australia. He also has an appointment with Curtin Institute of Radio Astronomy (CIRA) where he has been working since 2012. He is leading a group of engineers in the development of verification systems for the next-generation low-frequency aperture array (LFAA) at the Murchison Radio-astronomy Observatory (MRO) in Western Australia’s Mid-West. He received the Ph.D. degree in electrical engineering from the University of Calgary, Canada, in 2009. He has several years of industrial experience as an RF Engineer for Motorola in the Chicago area and for Murandi Communications Ltd. in Calgary. His interests include antennas, RF and microwave engineering, electromagnetics and radio astronomy engineering.