| 1. |
- Belitsky, Victor, 1955, et al.
(författare)
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ALMA Band 5 receiver cartridge: Design, performance, and commissioning
- 2018
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 611
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Tidskriftsartikel (refereegranskat)abstract
- We describe the design, performance, and commissioning results for the new ALMA Band 5 receiver channel, 163-211 GHz, which is in the final stage of full deployment and expected to be available for observations in 2018. This manuscript provides the description of the new ALMA Band 5 receiver cartridge and serves as a reference for observers using the ALMA Band 5 receiver for observations. At the time of writing this paper, the ALMA Band 5 Production Consortium consisting of NOVA Instrumentation group, based in Groningen, NL, and GARD in Sweden have produced and delivered to ALMA Observatory over 60 receiver cartridges. All 60 cartridges fulfil the new more stringent specifications for Band 5 and demonstrate excellent noise temperatures, typically below 45 K single sideband (SSB) at 4 K detector physical temperature and below 35 K SSB at 3.5 K (typical for operation at the ALMA Frontend), providing the average sideband rejection better than 15 dB, and the integrated cross-polarization level better than -25 dB. The 70 warm cartridge assemblies, hosting Band 5 local oscillator and DC bias electronics, have been produced and delivered to ALMA by NRAO. The commissioning results confirm the excellent performance of the receivers.
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| 2. |
- Belitsky, Victor, 1955, et al.
(författare)
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SEPIA - A new single pixel receiver at the APEX telescope
- 2018
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 612
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Tidskriftsartikel (refereegranskat)abstract
- Context. We describe the new Swedish-ESO PI Instrument for APEX (SEPIA) receiver, which was designed and built by the Group for Advanced Receiver Development (GARD), at Onsala Space Observatory (OSO) in collaboration with ESO. It was installed and commissioned at the APEX telescope during 2015 with an ALMA Band 5 receiver channel and updated with a new frequency channel (ALMA Band 9) in February 2016. Aim. This manuscript aims to provide, for observers who use the SEPIA receiver, a reference in terms of the hardware description, optics and performance as well as the commissioning results. Methods. Out of three available receiver cartridge positions in SEPIA, the two current frequency channels, corresponding to ALMA Band 5, the RF band 158-211 GHz, and Band 9, the RF band 600-722 GHz, provide state-of-the-art dual polarization receivers. The Band 5 frequency channel uses 2SB SIS mixers with an average SSB noise temperature around 45 K with IF (intermediate frequency) band 4-8 GHz for each sideband providing total 4 × 4 GHz IF band. The Band 9 frequency channel uses DSB SIS mixers with a noise temperature of 75-125 K with IF band 4-12 GHz for each polarization. Results. Both current SEPIA receiver channels are available to all APEX observers.
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| 3. |
- Ermakov, Andrey, 1960, et al.
(författare)
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Broken-step Phenomenon in SIS Mixers
- 2016
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Ingår i: 27th International Symposium on Space Terahertz Technology, ISSTT 2016, Nanjing, China.
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Konferensbidrag (refereegranskat)abstract
- In this paper, we discuss a “broken step” phenomenonin an SIS mixer. This phenomena was observed in the production version of the SIS mixers, designed for the 159-211 GHz RF band,being used for the construction of the ALMA Band 5 receiver The broken step typically appears at LO frequencies above 180 GHz and manifests itself as a sharp onset in the DC current at the middle of the quasiparticle step. Correspondingly, this affects the mixer IF response in a way that is similar to the Josephson step but is however of a different nature. Such behaviour affects the SIS mixer dynamic range and complicates the tuning of the 2SB mixer to optimize its performance, for both the receiver noise as well as the sideband rejection. In this paper, we describe results of a few experiments which were performed to understand this undesirable phenomenon.
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| 4. |
- Garrett, John, et al.
(författare)
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Spectral Domain Simulation of SIS Frequency Multiplication
- 2017
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Ingår i: 28th International Symposium on Space Terahertz Technology.
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Konferensbidrag (refereegranskat)abstract
- In this paper, we compare simulations to experimental results for a new SIS frequency multiplier. To simulate these devices, we developed software based on spectral-domain analysis, which is ideal for simulating higher-order harmonics such as those present in a multiplier. In addition, we included the embedding circuit and interpolated the experimental I-V curve to allow the simulation to capture the experimental system as closely as possible. For the experimental data, results were taken from a new SIS frequency multiplier that has recently been developed at the Chalmers University of Technology. Previously, these experimental results were compared to simulations based on Tucker theory. Here, we compare these results to spectral-domain simulations. Qualitatively, the inclusion of embedding impedances and the use of spectral-domain analysis improves the agreement between simulation and experiment. The software can now be used to design multipliers with high output power and high conversion efficiency
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| 5. |
- Krause, Sascha, 1989, et al.
(författare)
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Noise and IF Gain Bandwidth of a Balanced Waveguide NbN/GaN Hot Electron Bolometer Mixer Operating at 1.3 THz
- 2018
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Ingår i: IEEE Transactions on Terahertz Science and Technology. - 2156-342X .- 2156-3446. ; 8:3, s. 365-371
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we present the comprehensive characterization of a waveguide balanced phonon-cooled NbN hot electron bolometer (HEB) mixer on aGaNbuffer-layer operating at approximately 1.3 terahertz (THz). The measured uncorrected double sideband noise temperature was as low as 750 K at 1 GHz intermediate frequency (IF) and 900 K at 4 GHz IF, respectively, and suggests a noise bandwidth of 7 GHz. Moreover, the IF gain bandwidth of the HEB itself was deduced from a mixing experiment with a second monochromatic THz signal source and has shown a 3 dB roll-off at 5.5 GHz. The contribution of the HEB mixer on the overall receiver noise temperature was determined to be in the order of 300 K or 5 hf/k considering losses in the RF transmission path and the waveguide components as well as accounting for the receiver conversion loss, which was deduced from the U-factor method. The achieved performance sets a new benchmark for futureTHz instruments and emphasizes the technological readiness of waveguide-based NbN HEB mixers employing a GaN buffer-layer featuring significantly improved IF bandwidth without compromising on the receiver’s noise temperature.
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| 6. |
- Marouf Rashid, Hawal, 1982, et al.
(författare)
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Compact wideband passive and active component chips for radio astronomy instrumentation
- 2019
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Ingår i: ISSTT 2019 - 30th International Symposium on Space Terahertz Technology, Proceedings Book. ; , s. 50-56
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Konferensbidrag (refereegranskat)abstract
- In the 2SB receivers, the rejection ratio is determined among other factors by the performance of the quadrature hybrids. We have developed and fine‐tuned components that intended to be used in the IF chain and meet the requirements for new generation of compact wideband 2SB receivers. We present here the design and characterization of three multi‐section compact wideband 3 dB quadrature couplers (coupled line coupler – Lange coupler–coupled line coupler). Specifically, the miniaturized 3‐section hybrid chip made using thin‐film technology utilizes gold plated transmission lines and air bridges to connect the fingers of the Lange coupler (middle section The hybrids were designed to have the amplitude and phase imbalance better than 0.6 dB and ±3° respectively over a 3.5-12.5 GHz and 4-16 GHz frequency bands. Experimental verification of the assembly at 293 K and 4 K shows very good agreement between the measurements and simulations. Additionally, we demonstrate the suitability of the miniature hybrid chips, by implementing them in a balanced amplifier designed using a modular approach, which demonstrated promising results.
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| 7. |
- Marouf Rashid, Hawal, 1982, et al.
(författare)
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Design of Wideband Waveguide Hybrid With Ultra-Low Amplitude Imbalance
- 2016
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Ingår i: IEEE Transactions on Terahertz Science and Technology. - 2156-342X .- 2156-3446. ; 6:1, s. 83-90
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Tidskriftsartikel (refereegranskat)abstract
- We present a design and synthesis procedure for a new 90 ° waveguide hybrid with ultra-low amplitude imbalance. This novel hybrid design is based on Reed's multiple branch waveguide hybrid. The primary feature of this quadrature hybrid design is the introduction of a controllable ripple in the operational band by, firstly changing the heights of the input and output branches and, secondly, by introducing three waveguide-height discontinuity sections placed symmetrically in the main waveguide. This layout allows ultra-low amplitude imbalance over a wide operational band. At the same time, it permits a greater input/output branch height as compared to the Reed's 5-branch waveguide hybrid, which should ease fabrication for short-mm and sub-mm wavelengths. This design concept is demonstrated through a 90 ° waveguide hybrid for the 159-216 GHz band (30% fractional bandwidth). Our simulations indicate that the amplitude imbalance of the hybrid is better than 0.2 dB over the most of the 159-216 GHz band with a phase imbalance better than ±4°. Experimental verification of the hybrid shows excellent agreement with the simulations.
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| 8. |
- Marouf Rashid, Hawal, 1982, et al.
(författare)
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Experimental Verification of the pumping of SIS mixer with an Distributed SIS Frequency Doubler
- 2016
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Ingår i: International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz. - 2162-2027 .- 2162-2035. - 9781467384858 ; 2016-November, s. Art. no. 7758974-
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Konferensbidrag (refereegranskat)abstract
- In this paper, we present the performance of the first frequency multiplier using the non-linearity of distributed SIS junctions. The prototype doubler based on distributed SIS junction was for the first time able to pump an SIS mixer. The multiplication efficiency of the distributed SIS junction is 15-30 % for a fractional bandwidth of 10% with excellent spectral line purity. The measured -3 dB line width of the multiplied signal is better than 1 Hz, which was limited by the resolution bandwidth of the spectrum analyzer. The results attained in this work show that the distributed SIS junction frequency multipliers have considerable future potential, and could possibly be used in LO source in single-end and multi-pixel SIS mixer receivers.
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| 9. |
- Marouf Rashid, Hawal, 1982, et al.
(författare)
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Frequency Multiplier Based on Distributed Superconducting Tunnel Junctions: Theory, Design, and Characterization
- 2016
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Ingår i: IEEE Transactions on Terahertz Science and Technology. - 2156-342X .- 2156-3446. ; 6:5, s. 724-736
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we present the analysis, design, andcharacterization of the first frequency multiplier using distributed superconductor–insulator–superconductor (SIS) junctions. We derived analytical expressions describing the properties of the distributed SIS junction as a frequency multiplier. The modeling of the distributed SIS junctions shows that high conversion efficiency can be achieved when used as the multiplier. The measured outputpower generated by such multiplier employing the distributed SIS junction at the second harmonic of the input frequency is in good agreement with the model. Furthermore, the frequency multiplier based on the distributed SIS junction for the first time was able to pump an SIS mixer. The multiplication efficiency of thedistributed SIS junction is 15–30% for a fractional bandwidth of 10% with excellent spectral line purity. The –3 dB line width of the multiplied signal is 1 Hz, which was limited by the resolution bandwidth of the spectrum analyzer. The results attained in this paper show that the distributed SIS junction frequency multiplier has considerable future potential, and could possibly be used in LO source in single-end and multipixel SIS mixer receivers.
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| 10. |
- Marouf Rashid, Hawal, 1982, et al.
(författare)
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Harmonic and reactive behavior of the quasiparticle tunnel current in SIS junctions
- 2016
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Ingår i: AIP Advances. - : AIP Publishing. - 2158-3226 .- 2158-3226. ; 6:4
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we show theoretically and experimentally that the reactive quasiparticle tunnel current of the superconductor tunnel junction could be directly measured at specific bias voltages for the higher harmonics of the quasiparticle tunnel current. We used the theory of quasiparticle tunneling to study the higher harmonics of the quasiparticle tunnel current in superconducting tunnel junction in the presence of rf irradiation. The impact of the reactive current on the harmonic behavior of the quasiparticle tunnel current was carefully studied by implementing a practical model with four parameters to model the dc I-V characteristics of the superconducting tunnel junction. The measured reactive current at the specific bias voltage is in good agreement with our theoretically calculated reactive current through the Kramers-Kronig transform. This study also shows that there is an excellent correspondence betweenthe behavior of the predicted higher harmonics using the previously established theory of quasiparticle tunnel current in superconducting tunnel junctions by J.R. Tucker and M.J. Feldman and the measurements presented in this paper
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