Simulation and Testing of a Linear Array of Modified Four-Square Feed Antennas for the Tianlai Cylindrical Radio Telescope

Cianciara, Aleksander J.; Anderson, Christopher; Chen, Xuelei; Chen, Zhiping; Geng, Jin-Jun; Li, Jixia; Liu, Chao; Liu, Tao; Lu, Wing; Peterson, Jeffrey B.; Shi, Huli; Steffel, Catherine N.; Stebbins, Albert; Stucky, Thomas; Sun, Shijie; Timbie, Peter; Wang, Yougang; Wu, Fengquan; Zhang, Jie

doi:10.1142/s2251171717500039

Cited by 12 publications

(11 citation statements)

References 33 publications

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“…The sim-ulated beam profiles at 650, 1050 and 1420 MHz were reported earlier in ref. [29], which demonstrated that the Tianlai cylinder antennas and feeds have a quite good broadband response. Here, we show the simulated beam profiles in the 700-800 MHz range in Figure 13.…”

Section: The Antenna Beam Response Patternmentioning

confidence: 95%

“…The Tianlai cylinder reflector is fixed on the ground, and at any moment its FoV is a narrow strip running from north to south through the zenith. While the reflectors allow the FoV to run from horizon-tohorizon in the N-S direction, the beam of the feeds limits the strip to ±60 • from zenith [29]. As the Earth rotates, the beams scan the northern celestial hemisphere (The latitude of the telescope site is 44 • , so the FoV extends from −16 • declination up to +90 • and back down to +76 • on the other side).…”

Section: Instrumentsmentioning

confidence: 99%

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The Tianlai Cylinder Pathfinder array: System functions and basic performance analysis

Zuo

et al. 2020

Sci. China Phys. Mech. Astron.

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The Tianlai Cylinder Pathfinder is a radio interferometer array designed to test techniques for 21 cm intensity mapping in the post-reionization Universe, with the ultimate aim of mapping the large scale structure and measuring cosmological parameters such as the dark energy equation of state. Each of its three parallel cylinder reflectors is oriented in the north-south direction, and the array has a large field of view. As the Earth rotates, the northern sky is observed by drift scanning. The array is located in Hongliuxia, a radio-quiet site in Xinjiang, and saw its first light in September 2016. In this first data analysis paper for the Tianlai cylinder array, we discuss the subsystem qualification tests, and present basic system performance obtained from preliminary analysis of the commissioning observations during 2016-2018. We show typical interferometric visibility data, from which we derive the actual beam profile in the east-west direction and the frequency band-pass response. We describe also the calibration process to determine the complex gains for the array elements, either using bright astronomical point sources, or an artificial on site calibrator source, and discuss the instrument response stability, crucial for transit interferometry. Based on this analysis, we find a system temperature of about 90 K, and we also estimate the sensitivity of the array.

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Section: The Antenna Beam Response Patternmentioning

confidence: 95%

Section: Instrumentsmentioning

confidence: 99%

The Tianlai Cylinder Pathfinder array: System functions and basic performance analysis

Zuo

et al. 2020

Sci. China Phys. Mech. Astron.

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“…But the beam response of the Tianlai cylinder array has not been measured before. While a beam model was computed with electromagnetic field simulation (Cianciara et al 2017), it is based on the ideal model, while the actual construction could be different. Here we fit the beam profile from the observed data.…”

Section: Sky Source Calibrationmentioning

confidence: 99%

An Eigenvector-Based Method of Radio Array Calibration and Its Application to the Tianlai Cylinder Pathfinder

Zuo

Pen

et al. 2019

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We propose an eigenvector-based formalism for the calibration of radio interferometer arrays. In the presence of a strong dominant point source, the complex gains of the array can be obtained by taking the first eigenvector of the visibility matrix. We use the stable principle component analysis (SPCA) method to help separate outliers and noise from the calibrator signal to improve the performance of the method. This method can be applied with poorly known beam model of the antenna, and is insensitive to outliers or imperfections in the data, and has low computational complexity. It thus is particularly suitable for the initial calibration of the array, which can serve as the initial point for more accurate calibrations. We demonstrate this method by applying it to the cylinder pathfinder of the Tianlai experiment, which aims to measure the dark energy equation of state using the baryon acoustic oscillation (BAO) features in the large scale structure by making intensity mapping observation of the redshifted 21 cm emission of the neutral hydrogen (HI). The complex gain of the array elements and the beam profile in the East-West direction (short axis of the cylinder) are successfully obtained by applying this method to the transit data of bright radio sources.

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“…These simulations require realistic models of the telescope beams. Electromagnetic simulation codes such as CST, GRASP and HFSS can be used for this, but achieving the accuracy required is challenging computationally [98][99][100]. A complementary approach is to generate synthetic beams with sufficient complexity to capture the challenges posed by real beams.…”

Section: Simulation Needs and Challengesmentioning

confidence: 99%

Research and Development for HI Intensity Mapping

Timbie¹,

Ahmed²,

Alonso³

et al. 2019

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Development of the hardware, data analysis, and simulation techniques for large compact radio arrays dedicated to mapping the 21 cm line of neutral hydrogen gas has proven to be more difficult than imagined twenty years ago when such telescopes were first proposed. Despite tremendous technical and methodological advances, there are several outstanding questions on how to optimally calibrate and analyze such data. On the positive side, it has become clear that the outstanding issues are purely technical in nature and can be solved with sufficient development activity. Such activity will enable science across redshifts, from early galaxy evolution in the pre-reionization era to dark energy evolution at low redshift.

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Simulation and Testing of a Linear Array of Modified Four-Square Feed Antennas for the Tianlai Cylindrical Radio Telescope

Cited by 12 publications

References 33 publications

The Tianlai Cylinder Pathfinder array: System functions and basic performance analysis

The Tianlai Cylinder Pathfinder array: System functions and basic performance analysis

An Eigenvector-Based Method of Radio Array Calibration and Its Application to the Tianlai Cylinder Pathfinder

Research and Development for HI Intensity Mapping

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