| 11. |
- Nyström, Olle, 1979, et al.
(författare)
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Integrated Setup for THz Receiver Characterization
- 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. P6-4
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Konferensbidrag (refereegranskat)abstract
- A highly versatile measurement setup has been built that allows complete characterization of the ALMA Band 5 cartridge. The measurement setup includes all necessary hardware and largely achieves automatic measurements for the system noise and sideband rejection with in-built optimization procedures. The measurement setup additionally comprises measurements of the receiver saturation, phase and amplitude stability, as well as optical beam characterization.
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| 12. |
- Belitsky, Victor, 1955, et al.
(författare)
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A new 3 mm band receiver for the Onsala 20 m antenna
- 2015
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 580
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Tidskriftsartikel (refereegranskat)abstract
- A new receiver for the Onsala 20 m antenna with the possibility of being equipped with 3 mm and 4 mm bands has been built and the 3 mm channel has been commissioned during the Spring 2014. For single-dish operation, the receiver uses an innovative on-source/off-source optical switch. In combination with additional optical components and within the same optical layout, the switch provides two calibration loads (for the 3 mm and 4 mm channels), sideband rejection measurement, and tuning possibilities. The optical layout of the receiver employs all cold (4 K) offset elliptical mirrors for both channels, whereas the on-off switch employs flat mirrors only. The 3 mm channel employs a sideband separation (2SB) dual polarization receiver with orthomode transducer (OMT), 4-8 GHz intermediate frequency (IF), x? 2pol x? upper and lower sidebands (USB? +? LSB). The cryostat has four optical windows made of high density polyethylene (HDPE) with anti-reflection corrugations, two for the signal and two for each frequency band cold load. The cryostat uses a two-stage cryocooler produced by Sumitomo HI? RDK? 408D2 with anti-vibration suspension of the cold-head to minimize impact of the vibrations on the receiver stability. The local oscillator (LO) system is based on a Gunn oscillator with aphase lock loop (PLL) and four mechanical tuners for broadband operation, providing independently tunable LO power for each polarization. This paper provides a technical description of the receiver and its technology and could be useful for instrumentation engineers and observers using the Onsala 20 m telescope.
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| 13. |
- Billade, Bhushan, 1982, et al.
(författare)
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A Wide-band Feed System for SKA Band 1 Covering Frequencies From 350 - 1050 MHz
- 2016
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Ingår i: 10th European Conference on Antennas and Propagation, EuCAP 2016; Davos; Switzerland; 10 April 2016 through 15 April 2016. - 2164-3342. - 9788890701863 ; , s. Art. no. 7481794-
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Konferensbidrag (refereegranskat)abstract
- We present the design of a wideband feed system for the Band 1 of the Square Kilometer Array (project). The Band 1 feed system uses a quad-ridged flared horn (QRFH) optimizedfor a offset Gregorian dual reflector dish to cover RF frequencies from 350 - 1050 MHz, and a cryogenic low noise amplifier (LNA). The feed horn is optimized to achieve best Aeff/Tsys over the entire band, by making trade-off between aperture efficiency and spill over noise contribution. The optimised feed horn shows above 70% efficiency over the entire 3:1 band, with return loss better than 10 dB. The cryostat following the feed has between 9 to 14 K noise, measured at the co-axial connector of the QRFH. The estimated on-sky sensitivity of the feed system is better than specified 4.2 m2/K averaged over the entire frequency band.
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| 14. |
- Billade, Bhushan, 1982, et al.
(författare)
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ALMA Band 5 (163-211 GHz) Sideband Separating Mixer Design
- 2008
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Ingår i: in Proceedings of The 19th International Symposium on Space Terahertz Technology, Groningen, 28-30 April 2008, ed. W. Wild, Space Research Organization of the Netherlands (SRON). ; part I, s. 250-252
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Konferensbidrag (refereegranskat)
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| 15. |
- Billade, Bhushan, 1982, et al.
(författare)
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ALMA Band 5 (163-211 GHz) Sideband Separation Mixer
- 2009
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Ingår i: 20th international Symposium on Space and Terahertz technology, Charlottesville, VA, USA, April 20-22, 2009. ; , s. 19-23
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Konferensbidrag (refereegranskat)abstract
- We present the design of ALMA Band 5 sideband separation SIS mixer and experimental results for the double side band mixer and first measurement results 2SB mixer. In this mixer, the LO injection circuitry is integrated on the mixer substrate using a directional coupler, combining microstrip lines with slot-line branches in the ground plane. The isolated port of the LO coupler is terminated by wideband floating elliptical termination. The mixer employs two SIS junctions with junction area of 3 μm2 each, in the twin junction configuration, followed by a quarter wave transformer to match the RF probe. 2SB mixer uses two identical but mirrored chips, whereas each DSB mixer has the same end-piece configuration. The 2S mixer has modular design such that DSB mixers are measured independently and then integrated into 2SB simply by placing around the middle piece.Measurements of the DSB mixer show noise temperature ofaround 40K over the entire band. 2SB mixer is not fullycharacterized yet, however, preliminary measurement indicates SSB (un-corrected) noise temperature of 80K.
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| 16. |
- Billade, Bhushan, 1982, et al.
(författare)
-
ALMA Band 5 (163-211 GHz) sideband separation mixer design
- 2008
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Ingår i: Proceedings of the 19th International Symposium on Space Terahertz Technology, ISSTT 2008. ; , s. 231-233
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Konferensbidrag (refereegranskat)abstract
- We present the design of ALMA Band 5 sideband separation mixer based on Niobium superconducting SIS junctions and first experimental results for the double side band mixer. In this mixer the LO injection circuitry is integrated on the mixer substrate using a microstrip line directional coupler with slot-line branches in the ground plane. The isolated port of the LO coupler is terminated by a wideband floating elliptical termination. The mixer employs two SIS junctions with junction area of 3 ?m2 each, in twin junction configuration, followed by a quarter wave transformer to couple it to the RF probe. First measurements of the DSB mixer show promising results with noise temperature around 35K over the entire band.
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| 17. |
- Billade, Bhushan, 1982, et al.
(författare)
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An SIS Mixer With 2hf/k DSB Noise Temperature at 163–211 GHz Band
- 2013
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Ingår i: IEEE Transactions on Terahertz Science and Technology. - 2156-342X .- 2156-3446. ; 3:4, s. 416 - 421
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Tidskriftsartikel (refereegranskat)abstract
- We present the design and the performance of a fixed-tuned, all niobium (Nb) Superconductor–Insulator–Superconductor (SIS) mixer covering RF frequencies from 163 to 211 GHz with 4–8 GHz IF bandwidth. The mixer uses two Nb/Al-AlOx/Nb junctions of size 3 um each with the RnA product of 30 Ohn*squaremicron, in a twin junction configuration. An local oscillator (LO) directional coupler made of superconducting lines with slots in the ground plane is integrated on the SIS mixer chip. The isolated port of the LO coupler is terminated using a wide-band resistive load with a sheet resistance of 12 Ohm/square. The SIS tuning circuitry is optimized to achieve best power match between the twin junctions and the embedding circuitry. The measurement of the double sideband mixer noise at 171 GHz shows that the receiver noise temperature is approximately 17 K, which is just 2hf/k. The estimated noise contribution from the RF loss and the IF chain at 176 GHz LO frequency is 8 K and 7.5 K respectively, resulting in a SIS mixer noise of hf/2k. The mixer noise performance across the entire RF band varies between 19 to 25 K. This is to our knowledge the best reported noise temperature at these frequencies till now.
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| 18. |
- Billade, Bhushan, 1982
(författare)
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Design Of Dual Polarisation Sideband Separation Mixer For ALMA Band 5
- 2009
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This licentiate is focused on the design and development of Superconductor-Insulator-Superconductor (SIS) junction mixer for ALMA Band 5, one of the ten frequency bands of the Atacama Large Millimeter Array (ALMA) project. ALMA Band 5 is a dual polarisation sideband separation heterodyne receiver covering radio frequencies (RF) from 163 GHz to 211 GHz, with 4-8 GHz intermediate frequency (IF). Amongst the other ALMA bands, Band 5 is the lowest frequency band, which uses all-cold optics. That puts strong constrains on the dimensions of all the receiver components. For the SIS mixer, we employ a MMIC-like approach where most of the DSB mixer components, including LO injection circuitry with novel directional coupler, are integrated on the same crystal quartz substrate. The mixer uses a lumped filter technique to extract the IF frequencies, which is non-traditional for SIS mixers. A custom made superconducting Lange coupler with suspended air bridges to connect the fingers of Lange coupler is used. Experimental measurements of the double sideband mixer show state of the art performance with the receiver noise temperature below 30 Kelvin across the entire band. The noise temperature for sideband separation mixer is below 60 Kelvin with sideband rejection better than 12 dB over most of the band.
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| 19. |
- Billade, Bhushan, 1982, et al.
(författare)
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Experimental Study of Frequency Multiplication in a Distributed Array of SIS Junctions
- 2014
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Ingår i: IEEE Transactions on Terahertz Science and Technology. - 2156-342X .- 2156-3446. ; 4:2, s. 254-259
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Tidskriftsartikel (refereegranskat)abstract
- We report the first experimental off-chip detection of frequency multiplication in a distributed array of superconductor–insulator–superconductor (SIS) junctions. A test device consisting of series array of 68 Nb/Al-AlOx/Nb tunnel junctions was designed to study generation of the second harmonic in the 190–210 GHz band. The SIS array was exited with microwave radiation at 3-mm band using a quasi-optically coupled Gunn oscillator, and the output response of the device was studied using a double-sideband SIS mixer operating in the 163–211 GHz range with 4–8 GHz IF bandwidth. We measured extremely sharp spectral signals, associated with the $times 2$ frequency multiplication by the SIS array. Single and multi-photon processes were observed in the response of SIS tunnel junction-array to the applied microwave radiation, confirming device operation in the quantum mode. The output power of the multiplied signal increases linearly with the power of the pumping signal up to certain level and them saturates. In attempt to verify that the device produces noticeable power, the output of the test device was connected to the LO port of the SIS mixer, and an increase of 10%–20% in the SIS mixer dark current was observed. Further development of the demonstrated principle of frequency multiplication may lead to a practical frequency multiplier device.
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| 20. |
- Billade, Bhushan, 1982, et al.
(författare)
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Frequency Multiplication in a Distributed Array of SIS Junctions
- 2014
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Ingår i: Proceedings of the TWENTY-FIFTH INTERNATIONAL SYMPOSIUM ON SPACE TERAHERTZ TECHNOLOGY, April 27-30, 2014, Moscow, russia. ; , s. 68-
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Konferensbidrag (refereegranskat)abstract
- We report the experimental study of the off-chip detection of frequency multiplication in a distributed array of Superconductor-Insulator-Superconductor (SIS) junctions. A test device consisting of a series array consisting sixty eight Nb/Al-AlOx/Nb tunnel junctions was designed for this study, and was fabricated using in-house Nb thin-film technology. The test device with SIS array was optimized for the study of second harmonic generation in 182−192 GHz output frequency band. The SIS array was exited with microwave radiation at 3 mm band using a quasi-optically coupled Gunn oscillator and the output response of the device was studied using a double sideband SIS mixer operating in 163 − 211 GHz range with 4−8 GHz. The Josephson-effect for both the SIS multiplier and the detector mixer was carefully suppressed using magnetic field. We observed very sharp second harmonic spectral signals, due to frequency multiplication by the SIS array. We also observed distinct multi-photon process in the SIS array tunnel junction response to the applied microwave signal, and the amplitude of the multiplied signal shows dependence on the bias voltage of the SIS array. We observed that the output power of the multiplied signal increases linearly with the power of the pumping signal up to certain level and them saturates. Increasing the input power beyond this level results in the heating of the chip. When the output of the test device was connected to the LO port of the SIS-mixer, an increase of 10 − 20% in the SIS -mixer dark current was observed when the SIS mixer was voltage biased in the middle of first photon step below the gap voltage. The device, although far from providing sufficient power to pump a practical SIS mixer, may be considered as a first experimental step towards SIS frequency multipliers.
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