| 1. |
- Flygare, Jonas, 1988, et al.
(author)
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Wideband single pixel feed system over 4.6-24 GHz for the Square Kilometre Array
- 2019
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In: Proceedings of the 2019 21st International Conference on Electromagnetics in Advanced Applications, ICEAA 2019. ; , s. 630-635
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Conference paper (peer-reviewed)abstract
- We present the Band B feed system over 4.6-24 GHz designed for the Square Kilometre Array (SKA) reflector for radio astronomy applications. The feed is a Quad-ridge Flared Horn (QRFH) with a customized shape based on spline-defined profiles to achieve improved wideband performance. The feed system shows high aperture efficiency and sensitivity on the SKA reflector in predictions based on measured feed beam patterns. We present the feed design overview, cryogenic dewar concept and measurement of receiver noise (10-20 K) with wideband low-noise amplifiers, and full system simulation of the performance.
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| 2. |
- Hovey, Gary, 1955, et al.
(author)
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A framework for RFI simulation and performance verification
- 2019
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In: RFI 2019 - Proceedings of 2019 Radio Frequency Interference: Coexisting with Radio Frequency Interference.
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Conference paper (peer-reviewed)abstract
- Modern radio telescopes, like the proposed Square Kilometre Array (SKA), are extremely sensitive and the faint signals they receive can easily be contaminated irreversibly by stray radio frequency interference (RFI). Understanding how radio telescope performance is degraded by RFI is important. In this paper we describe an RFI simulation framework that can be used to generate test stimulus and verify a telescope's performance. The framework can be used during design to investigate the impact of various RFI scenarios and develop mitigation strategies. As well, it can be used to exercise and test hardware firmware after a system is installed. A prototype of the framework was implemented in the Python computer language to demonstrate the key concepts. Additionally, we outline the framework requirements, describe a suitable software structure and discuss a prototype implementation. As well, we present measurements made to verify the software generates correct test stimulus, for RFI from aircraft distance measuring equipment (DME). The work described was carried out to evaluate the impact of RFI on the Square Kilometre Array, an international effort to build the largest most sensitive radio telescope.
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| 3. |
- Hovey, Gary, 1955, et al.
(author)
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Characterization of the Beam and the Aperture of the Onsala Twin Telescopes
- 2023
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In: 2023 International Conference on Electromagnetics in Advanced Applications, ICEAA 2023. ; , s. 351-
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Conference paper (peer-reviewed)abstract
- Very Long Baseline Interferometry (VLBI) was originally developed to perform high angular resolution radio imaging, but it has also proven useful in geodesy. VLBI has played a key role in defining the International Celestial Reference Frame (ICRF), providing measurements of the Earth Orientation Parameters (EOP), and contributing to the International Terrestrial Reference Frame (ITRF) [1]. The legacy S/X VLBI systems have achieved positional accuracies of up to 5 mm.
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