| 1. |
- Belitsky, Victor, 1955, et al.
(författare)
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ALMA Band 2 Cold Cartridge Assembly Design
- 2022
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Ingår i: 32nd International Symposium of Space Terahertz Technology, ISSTT 2022.
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Konferensbidrag (refereegranskat)abstract
- As part of the ALMA development, we present the design of the ALMA Band 2 Cold Cartridge Assembly (CCA). The Band 2 is the last band that completes the suit of the 10 receiver channels of ALMA. The originally planned ALMA Band 2 receiver cartridge should cover the RF band of 67 - -90 GHz. The recent progress in technology, optics, OMT design and mm-wave amplifiers, however allowed to implement receiver that has an extended RF band up to 116 GHz. Furthermore, the Band 2 receiver pursues 2SB layout and provides 4-18 GHz IF band for two sidebands in a dual-polarization configuration. Here, we describe the design of the Band 2 CCA that includes optics, amplifier assembly, internal RF transport, mechanics and cryogenics. The downconverter part and performances are described elsewhere.
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| 2. |
- Meledin, Denis, 1974, et al.
(författare)
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SEPIA345: A 345 GHz dual polarization heterodyne receiver channel for SEPIA at the APEX telescope
- 2022
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 668
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Tidskriftsartikel (refereegranskat)abstract
- Context. We describe the new SEPIA345 heterodyne receiver channel installed at the Atacama Pathfinder EXperiment (APEX) telescope, including details of its configuration, characteristics, and test results on sky. SEPIA345 is designed and built to be a part of the Swedish ESO PI Instrument for the APEX telescope (SEPIA). This new receiver channel is suitable for very high-resolution spectroscopy and covers the frequency range 272- 376 GHz. It utilizes a dual polarization sideband separating (2SB) receiver architecture, employing superconductor-isolator-superconductor mixers (SIS), and provides an intermediate frequency (IF) band of 4- 12 GHz for each sideband and polarization, thus covering a total instantaneous IF bandwidth of 4 ÃÂ - 8 = 32 GHz. Aims. This paper provides a description of the new receiver in terms of its hardware design, performance, and commissioning results. Methods. The methods of design, construction, and testing of the new receiver are presented. Results. The achieved receiver performance in terms of noise temperature, sideband rejection, stability, and other parameters are described. Conclusions. SEPIA345 is a commissioned APEX facility instrument with state-of-the-art wideband IF performance. It has been available on the APEX telescope for science observations since July 2021.
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| 3. |
- Meledin, Denis, 1974, et al.
(författare)
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SEPIA345: a dual polarization 2SB cartridge receiver for APEX telescope: Design and Performance
- 2023
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Ingår i: Proceedings of the 32nd IEEE International Symposium on Space THz Technology.
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Konferensbidrag (refereegranskat)abstract
- A new receiver channel covering the 271-377 GHz frequency band has been installed into the SEPIA receiver at the APEX telescope. The receiver channel was designed and built in an ALMA-compatible cartridge layout. The receiver has a dual polarization layout with OMT and employs 2SB SIS mixers featuring an extended 4-12 GHz IF band, providing 32 GHz instantaneous IF bandwidth for two polarizations and two sidebands.
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| 4. |
- Meledin, Denis, 1974, et al.
(författare)
-
SEPIA345: a dual polarization 2SB cartridge receiver for APEX telescope: Design and Performance
- 2022
-
Ingår i: 32nd International Symposium of Space Terahertz Technology, ISSTT 2022.
-
Konferensbidrag (refereegranskat)abstract
- A new receiver channel covering the 271-377 GHz frequency band has been installed into the SEPIA receiver at the APEX telescope. The receiver channel was designed and built in an ALMA-compatible cartridge layout. The receiver has a dual polarization layout with OMT and employs 2SB SIS mixers featuring an extended 4-12 GHz IF band, providing 32 GHz instantaneous IF bandwidth for two polarizations and two sidebands.
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| 5. |
- Mebarki, Mohamed Aniss, 1993, et al.
(författare)
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Comparison of the low noise performance of GaN HEMTs and MIS-HEMTs at cryogenic temperatures
- 2023
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Ingår i: 2023 18th European Microwave Integrated Circuits Conference, EuMIC 2023. ; , s. 29-32
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Konferensbidrag (refereegranskat)abstract
- This work presents the comparison of the noise performance of AlGaN/GaN MIS-HEMTs and HEMTs at cryogenic temperatures. Wideband noise measurements at a physical temperature of 4K were performed in order to extract the noise characteristics of the devices, within the range of frequencies of 3-7 GHz. A DC and RF characterization of the devices are also presented to further assess their cryogenic performances. Over the measured frequency band, the results indicate that both technologies are able to present an average best noise temperature as low as 8 K. The MIS-HEMT presents a slight advantage at low bias condition, mainly due to its reduced gate capacitance. The presented results are the first report on the microwave low-noise performance of cryogenic GaN MIS-HEMT, and constitute their current state-of the art.
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| 6. |
- Mebarki, Mohamed Aniss, 1993, et al.
(författare)
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GaN HEMT with superconducting Nb gates for low noise cryogenic applications
- 2022
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Ingår i: 2022 Compound Semiconductor Week, CSW 2022.
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Konferensbidrag (refereegranskat)abstract
- We report on the successful integration of superconducting Nb gate electrodes to AlGaN/GaN heterostructures and HEMTs for low noise cryogenic applications. First, a specific Nb-gate process was developed and implemented on stand-alone gate test structures. The latter were tested at cryogenic temperatures down to 4 K, using DC end-to-end measurements. The results show a clear transition to a superconducting state at Tc ~ 9.2 K. The superconducting nature of the Nb gates further verified on actual HEMTs, featuring 2 fingers design with gate length of 0.2 μm, through their S-parameters measurements at T
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| 7. |
- Mebarki, Mohamed Aniss, 1993, et al.
(författare)
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GaN High-Electron-Mobility Transistors with Superconducting Nb Gates for Low-Noise Cryogenic Applications
- 2023
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Ingår i: Physica Status Solidi (A) Applications and Materials Science. - : Wiley. - 1862-6319 .- 1862-6300. ; 220:8
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Tidskriftsartikel (refereegranskat)abstract
- The successful integration of superconducting niobium (Nb) gate electrodes into cryogenic gallium nitride (GaN)-based high-electron-mobility transistors (HEMTs) is reported. This is achieved through a specifically developed microfabrication process. The device's DC, microwave, and noise performances at cryogenic temperatures, down to 4 K, are studied and presented. The superconductivity of the gate is tested using DC end-to-end measurements. A clear superconducting state transition at a critical temperature, Tc, of ≈9.2 K is shown. This is further verified with GaN HEMTs with two gate fingers and a gate length of 0.2 μm, through the extraction and validation of a small-signal model at T < Tc. Additionally, the superconductivity of the gate is verified for several gate widths and lengths, showing a significant reduction of the gate resistance independently of its dimensions. Finally, a comparative study of the cryogenic microwave noise performances of the GaN HEMTs with gold (Au) and Nb gates is presented. The Au-gated device presents a competitive optimum noise temperature, Tmin-opt, of ≈8 K at 5 GHz, demonstrating the potential of this technology for cryogenic low-noise applications. The Nb-gated device presents a 5 K higher Tmin-opt, which is found to be related to the suppression of the superconductivity of the Nb gate at the optimum-noise bias.
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| 8. |
- Mebarki, Mohamed Aniss, 1993, et al.
(författare)
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Noise Characterization and Modeling of GaN-HEMTs at Cryogenic Temperatures
- 2023
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Ingår i: IEEE Transactions on Microwave Theory and Techniques. - 0018-9480 .- 1557-9670. ; 71:5, s. 1923-1931
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Tidskriftsartikel (refereegranskat)abstract
- We report on the noise characterization and modeling of AlGaN/GaN high-electron-mobility transistors (HEMTs) at a cryogenic temperature (CT) of ∼ 10 K within the frequency range of 4.5–6.5 GHz. This work is the first model in the literature describing the high-frequency noise behavior of GaN-based HEMTs at CTs using a two-parameter-noise concept. The suggested model, which is based on measured noise figures and scattering parameters, provides the frequency and the bias dependence of the cryogenic noise properties of AlGaN/GaN HEMTs. The noise contributions from the intrinsic device, the parasitic network, and the gate leakage are separately extracted. The contribution of the access network is found in the order of 1 K and increases with the frequency, while the gate leakage has an impact of the order of 0.1 K and increases at low frequency. The model provides a basis for the future design and implementation of GaN-based cryogenic low-noise amplifiers.
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