A Multi-Feed Receiver in the 18 to 26.5 GHz Band for Radio Astronomy

Orfei, A.; Carbonaro, Luca; Cattani, A.; Cremonini, A.; Cresci, Luca; Fiocchi, F.; Maccaferri, A.; Maccaferri, G.; Mariotti, Sergio; Monari, Jader; Morsiani, M.; Natale, Vincenzo; Nesti, R.; Panella, D.; Poloni, M.; Roda, J.; Scalambra, A.; Tofani, G.

doi:10.1109/map.2010.5638236

Cited by 25 publications

(14 citation statements)

References 5 publications

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“…SRT is presently equipped with three cryogenic dualpolarisation receivers placed at different focal positions (Valente et al 2010, Navarrini et al 2016, Valente et al 2016, Navarrini et al 2017): a 7-beam K-band receiver (18−26.5 GHz, Gregorian focus), a mono-feed C-band receiver (5.7−7.7 GHz, Beam Wave Guide focal position), and a coaxial dual-feed L/P band receiver (0.305−0.41 GHz and 1.3−1.8 GHz, primary focus). A detailed description of the K−band multi-beam receiver is given in Orfei et al (2010). During the SRT ESP observations in 2016, the spectralpolarimetric backend SARDARA (SArdinia Roach2-based Digital Architecture for Radio Astronomy; Melis et al 2018) was configured in a mono-feed configuration.…”

Section: The K-band Setup With Srtmentioning

confidence: 99%

“…For the calibration of multi-feed data, we assumed that each feed (and polarisation channel) is characterised by a specific efficiency that is mostly due to the different noise temperatures of the individual electronic chains (Orfei et al 2010). We first evaluated a gain curve (as a function of the elevation) for the two polarisation channels of the central feed through OTF cross-scans on known flux density calibrators (3C286, 3C295, 3C147, 3C48 and NGC7027), and we adopted the Perley & Butler (2013) flux density scale.…”

Section: Data Calibration and Map Productionmentioning

confidence: 99%

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Investigating the high-frequency spectral features of SNRs Tycho, W44, and IC443 with the Sardinia Radio Telescope

Loru

Egron

Righini

et al. 2018

Monthly Notices of the Royal Astronomical Society

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The main characteristics in the radio continuum spectra of Supernova Remnants (SNRs) result from simple synchrotron emission. In addition, electron acceleration mechanisms can shape the spectra in specific ways, especially at high radio frequencies. These features are connected to the age and the peculiar conditions of the local interstellar medium interacting with the SNR. Whereas the bulk radio emission is expected at up to 20 − 50 GHz, sensitive high-resolution images of SNRs above 10 GHz are lacking and are not easily achievable, especially in the confused regions of the Galactic Plane. In the framework of the early science observations with the Sardinia Radio Telescope in February-March 2016, we obtained high-resolution images of SNRs Tycho, W44 and IC443 that provided accurate integrated flux density measurements at 21.4 GHz: 8.8 ± 0.9 Jy for Tycho, 25 ± 3 Jy for W44 and 66 ± 7 Jy for IC443. We coupled the SRT measurements with radio data available in the literature in order to characterise the integrated and spatially-resolved spectra of these SNRs, and to find significant frequency-and region-dependent spectral slope variations. For the first time, we provide direct evidence of a spectral break in the radio spectral energy distribution of W44 at an exponential cutoff frequency of 15 ± 2 GHz. This result constrains the maximum energy of the accelerated electrons in the range 6 − 13 GeV, in agreement with predictions indirectly derived from AGILE and Fermi-LAT gammaray observations. With regard to IC443, our results confirm the noticeable presence of a bump in the integrated spectrum around 20 − 70 GHz that could result from a spinning dust emission mechanism.

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Section: The K-band Setup With Srtmentioning

confidence: 99%

Section: Data Calibration and Map Productionmentioning

confidence: 99%

Investigating the high-frequency spectral features of SNRs Tycho, W44, and IC443 with the Sardinia Radio Telescope

Loru

Egron

Righini

et al. 2018

Monthly Notices of the Royal Astronomical Society

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“…The¯rst-light of SRT was obtained using the following three receivers: the L-and P-band dual-frequency coaxial receiver for primary-focus operations (Valente et al, 2010), the C-band monofeed receiver designed for the BWG layout I (Nesti et al, 2010;Orfei et al, 2011;Poloni, 2010;Peverini et al, 2011) and the K-band multi-feed receiver (seven corrugated feeds) for the secondary focus (Orfei et al, 2010).…”

Section: Microwave Receivers and Back-endsmentioning

confidence: 99%

Sardinia Radio Telescope: General Description, Technical Commissioning and First Light

Bolli

Orlati

Stringhetti

et al. 2015

J. Astron. Instrum.

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the Sardinia Radio Telescope (SRT) went through the technical commissioning phase. The characterization involved three¯rst-light receivers, ranging in frequency between 300 MHz and 26 GHz, connected to a Total Power back-end. It also tested and employed the telescope active surface installed in the main re°ector of the antenna. The instrument status and performance proved to be in good agreement with the expectations in terms of surface panels alignment (at present 300 m rms to be improved with microwave holography), gain ($0.6 K/Jy in the given frequency range), pointing accuracy (5 arcsec at 22 GHz) and overall single-dish operational capabilities. Unresolved issues include the commissioning of the receiver centered at 350 MHz, which was compromised by several radio frequency interferences, and a lower-than-expected aperture e±ciency for the 22-GHz receiver when pointing at low elevations. Nevertheless, the SRT, at present completing its Astronomical Validation phase, is positively approaching its opening to the scienti¯c community.

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“…Since a different feed is required per each beam, the need to cover all the directions in a determinate angular range is satisfied with a dense cluster of horns [12,13]. A similar multiple horn-fed reflector antenna system is employed in radio-astronomy too [14], where the low power of the typical signals involved requires a large parabolic dish to collect the incoming radiation and focus it in a feed.The feed has a composite geometry, and a certain numbers of horn antennas are placed close each other in the focal point, providing a multi-beam radiation where the beams system covers a wide span of the sky [15]. Since not the whole radio frequency (RF) system in charge of the signal processing consists of waveguide (WG) components, a suitable transition is required to connect the horn to the RF front-end without degrading the signal.…”

Section: Introductionmentioning

confidence: 99%

An In-Line Coaxial-to-Waveguide Transition for Q-Band Single-Feed-Per-Beam Antenna Systems

et al. 2021

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An in-line transition between a coaxial cable and rectangular waveguide operating in Q-band (33–50 GHz) is presented. The aim of the work is to minimize the modifications in the waveguide to the strictly necessary to overcome the manufacturing issues due to the high frequencies involved. In addition, the transition is compact and it does not increase the space occupation on the transverse section, this suggests its application in horn antennas clusters arrangement. The operating principle consists of both a modal conversion and an impedance matching between the devices. The modal conversion is realized in an intermediate region, where the coaxial penetrates in the waveguide: the device geometry is designed so that the electric field in the transition is a trade-off between the TEM mode of the coaxial and the TE10 of the guide. A shaped waveguide backshort and a reactive air gap in the coaxial cable co-participate to achieve the matching. An optimized Chebyshev stepped transformer completes the transition to fulfil the impedance mismatch with the full waveguide. The design issues and technological aspects are considered. The influences of the feeding pin misalignment, the presence of groove is included in the analysis and these practical aspects are discussed and numerically validated via the scattering parameters analysis of the proposed design. The return loss is higher than 25 dB over the whole Q-band.

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A Multi-Feed Receiver in the 18 to 26.5 GHz Band for Radio Astronomy

Cited by 25 publications

References 5 publications

Investigating the high-frequency spectral features of SNRs Tycho, W44, and IC443 with the Sardinia Radio Telescope

Investigating the high-frequency spectral features of SNRs Tycho, W44, and IC443 with the Sardinia Radio Telescope

Sardinia Radio Telescope: General Description, Technical Commissioning and First Light

An In-Line Coaxial-to-Waveguide Transition for Q-Band Single-Feed-Per-Beam Antenna Systems

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