| 1. |
- Amils, R. I., et al.
(författare)
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Compact cryogenic wide-band balanced amplifiers with superconducting 90° hybrids for the IF of submillimeter-wave SIS mixers
- 2019
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Ingår i: ISSTT 2019 - 30th International Symposium on Space Terahertz Technology, Proceedings Book. ; , s. 57-62
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Konferensbidrag (refereegranskat)abstract
- The pressing demand for mm-wave cryogenic radio astronomy receivers with increasing instantaneous bandwidth has spurred interest in more complex intermediate frequency amplifier configurations, like the balanced amplifier, as the traditional options have increasing difficulties to comply either with the noise or the input matching specifications. This solution is typically penalized by the slight increment in noise produced by the quadrature hybrid losses. We propose a balanced amplifier using a novel 3 dB quadrature hybrid coupler design with superconducting lines. The prototype unit built for the 4-12 GHz band integrates in the same module the hybrid coupler chips, the low noise amplifiers and the bias circuitry. The mechanical design allows for an independent testing of the individual amplifiers. The average noise temperature is 4.4 K, only 0.3 K more than the average of its amplifiers. The input reflection improves more than 10 dB. This compact balanced amplifier is also compared with a non-integrated version, showing an improvement in noise and reflection. It has been tested in a complete mm-wave receiver, with advantage over other IF schemes.
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| 2. |
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| 3. |
- Henke, D., et al.
(författare)
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Modeling SIS junction arrays for APEX band 3 (385-500 GHz)
- 2010
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Ingår i: 21st International Symposium on Space Terahertz Technology 2010, ISSTT 2010; Oxford; United Kingdom; 23 March 2010 through 25 March 2010. - 9781617823626 ; , s. 381-388
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Konferensbidrag (refereegranskat)abstract
- Abstract- A methodology for the modeling of superconductinginsulator- superconducting (SIS) junction arrays will be presented and compared with measured results. In many cases, junction arrays (either in parallel or series) are treated as a single equivalent junction. The APEX Band 3 (385-500 GHz) receiver design has been implemented with two junctions connected in parallel via a section of inductive microstrip line. In this case, it is desirable to separately model each junction as the pumping between junctions is no longer symmetrical across the entire band. Since the performance of the SIS junction depends on its terminating network, a complicated interaction occurs when another junction is part of the embedding impedance and, therefore, there remain aspects of its performance that are difficult to analyse. A simplified model, demonstrated with MATLAB, will be given and compared with a more complete model implemented using a common circuit simulator, Agilent ADS. In both cases, each junction is represented by a quasi 5-port network determined using the quantum theory of mixing. The model is then used to predict the performance of the APEX Band 3 mixer and compared with measured results.
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| 4. |
- Meledin, Denis, 1974, et al.
(författare)
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A 1mM SIS receiver utilizing different intermediate frequency (IF) configurations
- 2019
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Ingår i: ISSTT 2019 - 30th International Symposium on Space Terahertz Technology, Proceedings Book. ; , s. 164-167
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Konferensbidrag (refereegranskat)abstract
- We present experimental studies of the noise performance of a prototype heterodyne SIS receiver operating at wavelengths of about 1mm. The receiver employs different 4-12GHz intermediate frequency amplification chain configurations: a standalone low noise amplifier (LNA), the LNA cascading with a cryogenic isolator, and a low noise balanced amplifier. From our experiments and measurements, we could conclude that the latter configuration demonstrates the best broadband noise performance. In fact, the receiver equipped with the balanced LNA does not have noticeable noise degradation caused by the IF hybrids of the balanced LNA scheme. Moreover, our results indicate that even broader IF bandwidth of the receivers could be prospectively reached using balanced LNAs in the IF amplification chain.
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| 5. |
- 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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