Quasi-optical assessment of the ALMA band 9 front-end

Candotti, Massimo; Baryshev, A.; Trappe, Neil

doi:10.1016/j.infrared.2009.07.007

Cited by 9 publications

(5 citation statements)

References 9 publications

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“…Simulations and measurements agree extremely well. The main results were i) the first side lobes are at less than −22 dB below the main peak; ii) the beam squint between the polarizations is 9.2%; and iii) the aperture efficiency is above 80% at all frequencies and both polarizations (Candotti et al 2009). …”

Section: Rf Focusing and Lo Injectionmentioning

confidence: 97%

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The ALMA Band 9 receiver

Baryshev

Hesper

Mena

et al. 2015

A&A

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Aims. We describe the design, construction, and characterization of the Band 9 heterodyne receivers (600-720 GHz) for the Atacama Large Millimeter/submillimeter Array (ALMA). First-light Band 9 data, obtained during ALMA commissioning and science verification phases, are presented as well. Methods. The ALMA Band 9 receiver units (so-called "cartridges"), which are installed in the telescope's front end, have been designed to detect and down-convert two orthogonal linear polarization components of the light collected by the ALMA antennas. The light entering the front end is refocused with a compact arrangement of mirrors, which is fully contained within the cartridge. The arrangement contains a grid to separate the polarizations and two beam splitters to combine each resulting beam with a local oscillator signal. The combined beams are fed into independent double-sideband mixers, each with a corrugated feedhorn coupling the radiation by way of a waveguide with backshort cavity into an impedance-tuned superconductor-insulator-superconductor (SIS) junction that performs the heterodyne down-conversion. Finally, the generated intermediate frequency (IF) signals are amplified by cryogenic and room-temperature HEMT amplifiers and exported to the telescope's IF back end for further processing and, finally, correlation. Results. The receivers have been constructed and tested in the laboratory and they show an excellent performance, complying with ALMA requirements. Performance statistics on all 73 Band 9 receivers are reported. Importantly, two different tunnel-barrier technologies (necessitating different tuning circuits) for the SIS junctions have been used, namely conventional AlO x barriers and the more recent high-current-density AlN barriers. On-sky characterization and tests of the performance of the Band 9 cartridges are presented using commissioning data. Continuum and line images of the low-mass protobinary IRAS 16293-2422 are presented which were obtained as part of the ALMA science verification program. An 8 GHz wide Band 9 spectrum extracted over a 0.3 × 0.3 region near source B, containing more than 100 emission lines, illustrates the quality of the data.

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Section: Rf Focusing and Lo Injectionmentioning

confidence: 97%

“…A detailed description of these dimensions is given in Baryshev & Wild (2001). Furthermore, the whole system was verified using a full physical optics method (Candotti et al 2009). …”

Section: Rf Focusing and Lo Injectionmentioning

confidence: 99%

The ALMA Band 9 receiver

Baryshev

Hesper

Mena

et al. 2015

A&A

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“…Due to these benefits, QON is widely utilized in millimeter and submillimeter wave remote sensing and radioastronomy applications [1]. Many missions have been or are being developed, such as the five frequencies' band MASTER limb sounding instrument [2], the three bands' MARSCHALS simulator [3], the Herschel and Planck space telescopes [4][5][6], the ALMA front-end system [7,8], and the underway Chinese FY-4 meteorological satellite whose working frequencies are 54, 118, 183, 380, and 425 GHz [9].…”

Section: Introductionmentioning

confidence: 99%

Numerical and Experimental Verification of a 3D Quasi-Optical System

Liu

Hai

et al. 2015

International Journal of Antennas and Propagation

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A modular and efficient Gaussian beam (GB) analysis method, incorporating frame-based Gabor transformation, GB reflection, and a 3D GB diffraction technique, was developed to analyze both the reflectors and frequency selective surface (FSS) in quasioptical (QO) system. To validate this analysis method, a 3D dual-channel QO system operating at 183 and 325 GHz was designed and tested. The proposed QO system employs two-layer structure with a FSS of perforated hexagonal array transmitting the 325 GHz signal on the top layer while diverting the 183 GHz signal to the bottom layer. Measured results of the system demonstrate that the agreement can be achieved down to −30 dB signal level for both channels in the far field pattern. The discrepancy between the calculation and measurement is within 2 dB in the main beam region (2.5 times −3 dB beamwidth), verifying the effectiveness and accuracy of the proposed method.

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“…1) that contains telescope relay, polarization splitting, and LO injection optics. As is discussed in [9] in more detail, the design of this assembly has specifically aimed to allow the optics to be assembled without the need for optical alignment. In particular, the precision of modem CNC machines is sufficient to ensure that the surface shape and alignment accuracies of the mirrors are sufficient to ensure that the cartridge's quasioptical beam shape and alignment are within the project's requirements.…”

Section: Cartridge Designmentioning

confidence: 99%

“…Past work included the 0-7803-9348-1/05/$20.00 @2005 IEEE MB3-1 development of a SIS mixer test system [3] and a roomtemperature near-field beam measurement system [9], while a system is now being developed for testing the cartridges. This cartridge test system is based upon a cryostat that was developed by the National Astronomical Observatory of Japan, which simulates the environment of the ALMA cryostat, but for a single cartridge.…”

Section: Cartridge Test Systemmentioning

confidence: 99%

Design and Performance of the 600-720 GHz ALMA Band 9 Cartridge

Baryshev

Hesper

Jackson³

et al.

2005 Joint 30th International Conference on Infrared and Millimeter Waves and 13th International Conference on Terahertz Electr

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The ALMA Band 9 cartridge is a compact receiver unit for the Atacama Large Millimeter Array (ALMA) containing the core of a 600-720 GHz heterodyne front end, including a solid-state local oscillator; broadband SIS mixers; and a 4-12 GHz IF amplifier chain. This paper describes the design and performance of the first Band 9 cartridge. The experience gained with this unit is being used to optimize the design in preparation for the production of sufficient cartridges to fully populate the ALMA and ALMA Compact Arrays (ultimately requiring roughly 80 cartridges).

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Quasi-optical assessment of the ALMA band 9 front-end

Cited by 9 publications

References 9 publications

The ALMA Band 9 receiver

The ALMA Band 9 receiver

Numerical and Experimental Verification of a 3D Quasi-Optical System

Design and Performance of the 600-720 GHz ALMA Band 9 Cartridge

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