SKA AA-low front-end developments (At Cambridge University)

Acedo, Eloy de Lera; Razavi-Ghods, Nima; Scott, Paul F.; Doherty, Peter; Grainge, Keith; Faulkner, A. J.; Alexander, Paul; González‐Ovejero, David; Raucy, Christopher; Craeye, Christophe; Drought, Nick; Troop, Nick; Merwe, Paul van der; Reader, H.C.

doi:10.1109/eucap.2012.6206593

Cited by 13 publications

(11 citation statements)

References 7 publications

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“…Fig. 10 illustrates the spatial filtering property of an interferometer in one dimension described by (5). For simplicity, consider only the real part of (5).…”

Section: B Brief Review Of Radio Interferometrymentioning

confidence: 99%

Characterization of a Low-Frequency Radio Astronomy Prototype Array in Western Australia

Sutinjo

Colegate

Wayth

et al. 2015

IEEE Trans. Antennas Propagat.

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Abstract-We report characterization results for an engineering prototype of a next-generation low-frequency radio astronomy array. This prototype, which we refer to as the Aperture Array Verification System 0.5 (AAVS0.5), is a sparse pseudo-random array of 16 log-periodic antennas designed for 70-450 MHz. It is co-located with the Murchison Widefield Array (MWA) at the Murchison Radioastronomy Observatory (MRO) near the Australian Square Kilometre Array (SKA) core site. We characterize the AAVS0.5 using two methods: in-situ radio interferometry with astronomical sources and an engineering approach based on detailed full-wave simulation. Insitu measurement of the small prototype array is challenging due to the dominance of the Galactic noise and the relatively weaker calibration sources easily accessible in the southern sky. The MWA, with its 128 "tiles" and up to 3 km baselines, enabled in-situ measurement via radio interferometry. We present array sensitivity and beam pattern characterization results and compare to detailed full-wave simulation. We discuss areas where differences between the two methods exist and offer possibilities for improvement. Our work demonstrates the value of the dual astronomy-simulation approach in upcoming SKA design work.

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“…Fig. 10 illustrates the spatial filtering property of an interferometer in one dimension described by (5). For simplicity, consider only the real part of (5).…”

Section: B Brief Review Of Radio Interferometrymentioning

confidence: 99%

Characterization of a Low-Frequency Radio Astronomy Prototype Array in Western Australia

Sutinjo

Colegate

Wayth

et al. 2015

IEEE Trans. Antennas Propagat.

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“…In these simulations there is an infinite ground plane below the antenna and open boundary conditions everywhere else. The model is shown in Fig 7. In [8] we already demonstrated the accuracy of similar scale prototypes when measured in the open air environment. Here, a calibrated vector network analyser (VNA) was operated in TD mode to produce a non-dispersed pulse, with frequency components from 0.05-6 GHz.…”

Section: Scale Model Measurementsmentioning

confidence: 81%

“…6). This is where the low noise amplifiers (LNAs) will be connected in the real model [8]. The S and F-parameters measured at the ports located at the top of the antenna give an expression for the power reaching the ports due to the direct-injection and plane wave excitations respectively.…”

Section: Electromagnetic Modelling Of Lightning Effectsmentioning

confidence: 99%

EM modelling of lightning effects on SKA-low array antennas

Cole

Acedo

Reader

2013

2013 International Conference on Electromagnetics in Advanced Applications (ICEAA)

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In this paper we discuss the issue of lightning in low frequency arrays for radio astronomy with the SKA telescope in mind. The non-linear nature of the lightning makes it impossible with present computational codes to derive accurate pictures of lightning current effects on large, galvanically-connected structures. We consider a linearised approach to model idealised lightning with a focus on indirect strikes. The intention is to build up an understanding of minimising lightning damage and associated RFI in the arrays. Finally, we discuss the advantages of scale prototype measurements and time gating as expedient techniques to characterize these effects in controlled environments.

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“…1). The mechanical design of SKALA has now been further developed for improved mechanical performance [8] and it is now facing a next stage of development for mass production. Two test arrays of 16 SKALA elements (AAVS0 in UK [9] and AAVS05 in Australia [10]) have also been extensively tested to validate the performance of SKALA.…”

Section: )mentioning

confidence: 99%

Designing antennas for the aperture array SKA-low instrument; a system perspective

Acedo

Razavi-Ghods

Faulkner

et al. 2014

2014 16th International Symposium on Antenna Technology and Applied Electromagnetics (ANTEM)

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This paper describes the important design aspects of an array antenna for the low frequency instrument of the SKA telescope (SKA-low). The most important considerations to meet the telescope performance requirements are discussed. Finally, a plot of the expected sky brightness sensitivity for phase I of the SKA using log-periodic antennas is presented. Keywords-radio astronommy; log-periodic antenna; system designI.

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SKA AA-low front-end developments (At Cambridge University)

Cited by 13 publications

References 7 publications

Characterization of a Low-Frequency Radio Astronomy Prototype Array in Western Australia

Characterization of a Low-Frequency Radio Astronomy Prototype Array in Western Australia

EM modelling of lightning effects on SKA-low array antennas

Designing antennas for the aperture array SKA-low instrument; a system perspective

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