Wideband dual polarized line feed development for a cylindrical reflector radio telescope

Leung, M.; Kot, J.S.; Jones, Bevan

doi:10.1109/aps.2007.4395898

Cited by 9 publications

(8 citation statements)

References 4 publications

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“…Feeds -The HIRAX feed will be based on the feed used for CHIME, 36 a dual-polarized clover-leaf shaped dipole antenna that was in turn based on a four-square antenna developed for Molonglo. 37 The CHIME feed has low-loss and small reflectivity characteristics across a wide band and is composed of: (i) a FR4-dielectric printed circuit board (PCB) which has four metalized curved petals to act as a wide-band dipole antenna, (ii) a low-loss teflon material ¶ balun for impedance matching, and (iii) a teflon support board. The signal current distribution, design parameters, and beam characteristics are described in detail in Refs.…”

Section: Antennas: Dishes and Feedsmentioning

confidence: 99%

HIRAX: a probe of dark energy and radio transients

et al. 2016

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The Hydrogen Intensity and Real-time Analysis eXperiment (HIRAX) is a new 400-800 MHz radio interferometer under development for deployment in South Africa. HIRAX will comprise 1024 six meter parabolic dishes on a compact grid and will map most of the southern sky over the course of four years. HIRAX has two primary science goals: to constrain Dark Energy and measure structure at high redshift, and to study radio transients and pulsars. HIRAX will observe unresolved sources of neutral hydrogen via their redshifted 21-cm emission line ('hydrogen intensity mapping'). The resulting maps of large-scale structure at redshifts 0.8-2.5 will be used to measure Baryon Acoustic Oscillations (BAO). BAO are a preferential length scale in the matter distribution that can be used to characterize the expansion history of the Universe and thus understand the properties of Dark Energy. HIRAX will improve upon current BAO measurements from galaxy surveys by observing a larger cosmological volume (larger in both survey area and redshift range) and by measuring BAO at higher redshift when the expansion of the universe transitioned to Dark Energy domination. HIRAX will complement CHIME, a hydrogen intensity mapping experiment in the Northern Hemisphere, by completing the sky coverage in the same redshift range. HIRAX's location in the Southern Hemisphere also allows a variety of cross-correlation measurements with large-scale structure surveys at many wavelengths. Daily maps of a few thousand square degrees of the Southern Hemisphere, encompassing much of the Milky Way galaxy, will also open new opportunities for discovering and monitoring radio transients. The HIRAX correlator will have the ability to rapidly and efficiently detect transient events. This new data will shed light on the poorly understood nature of fast radio bursts (FRBs), enable pulsar monitoring to enhance long-wavelength gravitational wave searches, and provide a rich data set for new radio transient phenomena searches. This paper discusses the HIRAX instrument, science goals, and current status.

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Section: Antennas: Dishes and Feedsmentioning

confidence: 99%

HIRAX: a probe of dark energy and radio transients

et al. 2016

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“…It is a modification of the four-square feeds developed for the Molonglo Observatory. 21 The feed petals, balun stem, and support base are all made from printed circuits boards (PCB), as shown in Figure 5a. As shown in Figure 5b, the petals have curved outer edges that broaden the frequency response by reducing the number of individual resonant dimensions.…”

Section: Feedmentioning

confidence: 99%

Canadian Hydrogen Intensity Mapping Experiment (CHIME) pathfinder

et al. 2014

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A pathfinder version of CHIME (the Canadian Hydrogen Intensity Mapping Experiment) is currently being commissioned at the Dominion Radio Astrophysical Observatory (DRAO) in Penticton, BC. The instrument is a hybrid cylindrical interferometer designed to measure the large scale neutral hydrogen power spectrum across the redshift range 0.8 to 2.5. The power spectrum will be used to measure the baryon acoustic oscillation (BAO) scale across this poorly probed redshift range where dark energy becomes a significant contributor to the evolution of the Universe. The instrument revives the cylinder design in radio astronomy with a wide field survey as a primary goal. Modern low-noise amplifiers and digital processing remove the necessity for the analog beamforming that characterized previous designs. The Pathfinder consists of two cylinders 37 m long by 20 m wide oriented northsouth for a total collecting area of 1,500 square meters. The cylinders are stationary with no moving parts, and form a transit instrument with an instantaneous field of view of ∼100 degrees by 1-2 degrees. Each CHIME Send correspondence to K.Bandura: E-mail: kevin.bandura@mcgill.ca arXiv:1406.2288v1 [astro-ph.IM] 9 Jun 2014Pathfinder cylinder has a feedline with 64 dual polarization feeds placed every ∼30 cm which Nyquist sample the north-south sky over much of the frequency band. The signals from each dual-polarization feed are independently amplified, filtered to 400-800 MHz, and directly sampled at 800 MSps using 8 bits. The correlator is an FX design, where the Fourier transform channelization is performed in FPGAs, which are interfaced to a set of GPUs that compute the correlation matrix. The CHIME Pathfinder is a 1/10th scale prototype version of CHIME and is designed to detect the BAO feature and constrain the distance-redshift relation.The lessons learned from its implementation will be used to inform and improve the final CHIME design.

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“…The four-square antenna has a long history [11,14,32,36,43,44], particularly as a feed antenna for cylindrical reflectors [7,19,24,25]. In the traditional four-square antenna the radiators are flat, square conductors, approximately λ/2 along the diagonal from 'tip to tip,' and located ≈ λ/4 in front of a ground plane.…”

Section: 'Four-hex' Feed Antenna 31 Designmentioning

confidence: 99%

“…For an interferometer, the mapping speed is proportional to the total number of beams. Cylindrical telescopes currently in use include MOST [25], CHIME [7,9,34], and Ooty [45]. Tianlai's cylindrical reflectors are located side-by-side with their long axes oriented along the N-S direction.…”

Section: Introductionmentioning

confidence: 99%

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

Cianciara

Anderson

Chen

et al. 2017

J. Astron. Instrum.

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A wide bandwidth, dual polarized, modi¯ed four-square antenna is presented as a feed antenna for radio astronomical measurements. A linear array of these antennas is used as a line-feed for cylindrical re°ectors for Tianlai, a radio interferometer designed for 21 cm intensity mapping. Simulations of the feed antenna beam patterns and scattering parameters are compared to experimental results at multiple frequencies across the 650-1420 MHz range. Simulations of the beam patterns of the combined feed array/re°ector are presented as well.

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Wideband dual polarized line feed development for a cylindrical reflector radio telescope

Cited by 9 publications

References 4 publications

HIRAX: a probe of dark energy and radio transients

HIRAX: a probe of dark energy and radio transients

Canadian Hydrogen Intensity Mapping Experiment (CHIME) pathfinder

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

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