Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

IEEE Transactions on Applied Superconductivity

A 125-180 GHz fixed-tuned SIS mixer for radioastronomy

Alexandre Karpov, J. Blondel, P. Pasturel, K. H. Gundlach

Published Jun 1, 1997• 6 citations
Publisher

Abstract

An ultra low noise fixed-tuned SIS mixer covering an instantaneous band of 45% around 150 GHz has been developed for radioastronomy. A new type of coplanar tuning circuit for the SIS junction is introduced. The Nb/Al oxide/Nb junctions are 2 /spl mu/m/sup 2/ with critical Josephson current density of 4.2 KA/cm/sup 2/. The minimum DSB mixer noise is 11 K. The minimum DSB receiver noise is 19 K, while the average noise is 25 K in the 130-175 GHz range with a 1 GHz IF band. A speedup of the observations by a factor 2-3 is possible with the new receiver at 30 m IRAM radiotelescope.

DOI
10.1109/77.614710

Related papers

A 125-180 GHz fixed-tuned SIS mixer for radioastronomy

Alexandre Karpov, J. Blondel, P. Pasturel +1 more

A fixed-tuned SIS mixer covering an instantaneous band of 45% around 150 GHz has been developed for radioastronomy. A new type of coplanar tuning circuit for the SIS junction is introduced. The minimum DSB receiver noise is 19 K, while the average noise is 25K in the 130-175 GHz range with a 1 GHz IF band. A speedup of the observations by a factor 2-3 is possible with the new receiver.

European Microwave Conference (EuMC)•Oct 1, 1996•0 citations

A broad band low noise SIS radiometer

Alexandre Karpov, J. Blondel, P. Dmitriev +1 more

A new type of ultra broad band SIS low noise radiometer has been developed. The SIS receiver instantaneous band of about 30% is significantly increased compared to traditional designs. We avoid a restriction related to the limited band of the Intermediate Frequency (IF) low noise amplifier by using a multifrequency heterodyne power source. In this regime the frequency mixing is performed simultaneously in a big number of the subbands and the IF signals are combined in a common amplifier. A low noise operation in this regime is possible due to the quantum nature of the frequency mixing in SIS quasi particle tunnel junctions. The SIS receiver covers 25 GHz band centered at 90 GHz with an equivalent noise temperature of about 50 K. The receiver uses a fixed tuned SIS mixer with Nb/Al Ox/Nb junctions. The critical Josephson current density is about 2.6 KA/cm/sup 2/ and the junction area is of about 1.5 /spl mu/m/sup 2/. The limits to further improvement of the radiometer and the possibilities for extension of the technique to the sub millimeter band are discussed.

IEEE Transactions on Applied Superconductivity•Jun 1, 1999•1 citation

A 547 GHz SIS receiver employing a submicron Nb junction with an integrated matching circuit

Pascal Febvre, William R. McGrath, P. D. Batelaan +4 more

A heterodyne receiver using an SIS (superconductor-insulator-superconductor) waveguide mixer with two mechanical tuners has been built and characterized over the frequency range of 460 GHz to 630 GHz. This receiver is designed for radioastronomy applications. The mixer uses high-current-density, 0.25- mu m/sup 2/, Nb/AlO/sub x//Nb SIS tunnel junctions with integrated superconductive RF circuits to tune the junction capacitance. A DSB (double sideband) receiver noise temperature as low as 200+or-17 K has been obtained at 540 GHz. In addition, negative differential resistance has been observed in the DC I-V (current-voltage) curve at 487-491 GHz.>

IEEE MTT-S International Microwave Symposium digest•Dec 30, 2002•4 citations

Low Noise 1.2 THz SIS Receiver

Alexandre Karpov, David A. B. Miller, F. Rice +4 more

We present the development of a low noise superconductor insulator superconductor (SIS) mixer for the 1.1 - 1.25 THz heterodyne receiver of FIRST space radiotelescope. The quasi-optical SIS mixer has two NbTiN/AlN/Nb junctions with critical current density 30 kA/sq cm. The individual junction area is close to 0.65 square micrometers. The SIS junctions are coupled to the optical input beam through a planar double slot antenna and a Si hyperhemispherical lens. The minimum DSB receiver noise temperature is 650 K, about 12 hv/k.

Softwaretechnik-Trends•Dec 1, 2001•7 citations

Noise and gain in frequency mixers with NbN SIS junctions

Alexandre Karpov, B. Plathner, J. Blondel +4 more

We study noise and conversion gain in the SIS mixers with Nb/MgO/NbN junctions at the millimeter and submillimeter wavelengths in order to estimate the possibility to extent the low noise operation towards the theoretical limit of 4/spl Delta//h=2.4 THz. We present as preliminary result the lowest achieved receiver noise with NbN SIS junctions of 65 K with conversion gain of -6 dB at 162 GHz and 230 K receiver noise with conversion gain of -10 dB at 306 GHz. The junction area is 2 /spl mu/m/sup 2/ and Josephson critical current density is 1.4 KA/cm/sup 2/. The optimum R/sub N//spl omega/C of NbN junction for mixers is estimated as 600 GHz/V. In preliminary tests the junctions R/sub N//spl omega/C is 10-20 time superior to the optimum and a significant improvement of NbN SIS mixers may be expected. The noise sources in the NbN SIS junctions are studied and a possible mixer sensitivity improvement is discussed. The thermal properties of the SIS NbN are studied. The frequency limit of the low loss integrated tuning structure in NbN is estimated as at least as 1.5 THz.

IEEE Transactions on Applied Superconductivity•Jun 1, 1997•9 citations

Low Noise 1 THz SIS Mixer for Stratospheric Observatory: Design and Characterization

Alexandre Karpov, D A Miller, J. A. Stern +5 more

We report the development of a low noise SIS mixer aimed for 1 THz channel of the Caltech Airborne Submillimeter Interstellar Medium Investigations Receiver (CASIMIR), designed for the Stratospheric Observatory for Far Infrared Astronomy (SOFIA). The mixer uses Nb/Al-AlN/NbTiN SIS junctions with critical current density of about 45 kA/cm2. The junctions are shaped in order to optimize the suppression of the Josephson DC currents. We used a double slot planar antenna to couple the mixer chip with the telescope beam. The RF matching microcircuit is made using Nb and gold films. The mixer IF circuit is designed to cover 4-8 GHz band. The test receiver with the new mixer has the low noise operation in a 0.9-1.05 THz band. The minimum DSB receiver noise measured at 1 THz is 260 K (Y=1.64) , apparently the lowest reported up to date.

IEEE Transactions on Applied Superconductivity•Mar 22, 2011•6 citations
An ultra low noise fixed-tuned SIS mixer covering an instantaneous band of 45% around 150 GHz has been developed for radioastronomy. A new type of coplanar tuning circuit for the SIS junction is introduced. The Nb/Al oxide/Nb junctions are 2 /spl mu/m/sup 2/ with critical Josephson current density of 4.2 KA/cm/sup 2/. The minimum DSB mixer noise is 11 K. The minimum DSB receiver noise is 19 K, while the average noise is 25 K in the 130-175 GHz range with a 1 GHz IF band. A speedup of the observations by a factor 2-3 is possible with the new receiver at 30 m IRAM radiotelescope.
A new type of ultra broad band SIS low noise radiometer has been developed. The SIS receiver instantaneous band of about 30% is significantly increased compared to traditional designs. We avoid a restriction related to the limited band of the Intermediate Frequency (IF) low noise amplifier by using a multifrequency heterodyne power source. In this regime the frequency mixing is performed simultaneously in a big number of the subbands and the IF signals are combined in a common amplifier. A low noise operation in this regime is possible due to the quantum nature of the frequency mixing in SIS quasi particle tunnel junctions. The SIS receiver covers 25 GHz band centered at 90 GHz with an equivalent noise temperature of about 50 K. The receiver uses a fixed tuned SIS mixer with Nb/Al Ox/Nb junctions. The critical Josephson current density is about 2.6 KA/cm/sup 2/ and the junction area is of about 1.5 /spl mu/m/sup 2/. The limits to further improvement of the radiometer and the possibilities for extension of the technique to the sub millimeter band are discussed.
A heterodyne receiver using an SIS (superconductor-insulator-superconductor) waveguide mixer with two mechanical tuners has been built and characterized over the frequency range of 460 GHz to 630 GHz. This receiver is designed for radioastronomy applications. The mixer uses high-current-density, 0.25- mu m/sup 2/, Nb/AlO/sub x//Nb SIS tunnel junctions with integrated superconductive RF circuits to tune the junction capacitance. A DSB (double sideband) receiver noise temperature as low as 200+or-17 K has been obtained at 540 GHz. In addition, negative differential resistance has been observed in the DC I-V (current-voltage) curve at 487-491 GHz.>
We present the development of a low noise superconductor insulator superconductor (SIS) mixer for the 1.1 - 1.25 THz heterodyne receiver of FIRST space radiotelescope. The quasi-optical SIS mixer has two NbTiN/AlN/Nb junctions with critical current density 30 kA/sq cm. The individual junction area is close to 0.65 square micrometers. The SIS junctions are coupled to the optical input beam through a planar double slot antenna and a Si hyperhemispherical lens. The minimum DSB receiver noise temperature is 650 K, about 12 hv/k.
We study noise and conversion gain in the SIS mixers with Nb/MgO/NbN junctions at the millimeter and submillimeter wavelengths in order to estimate the possibility to extent the low noise operation towards the theoretical limit of 4/spl Delta//h=2.4 THz. We present as preliminary result the lowest achieved receiver noise with NbN SIS junctions of 65 K with conversion gain of -6 dB at 162 GHz and 230 K receiver noise with conversion gain of -10 dB at 306 GHz. The junction area is 2 /spl mu/m/sup 2/ and Josephson critical current density is 1.4 KA/cm/sup 2/. The optimum R/sub N//spl omega/C of NbN junction for mixers is estimated as 600 GHz/V. In preliminary tests the junctions R/sub N//spl omega/C is 10-20 time superior to the optimum and a significant improvement of NbN SIS mixers may be expected. The noise sources in the NbN SIS junctions are studied and a possible mixer sensitivity improvement is discussed. The thermal properties of the SIS NbN are studied. The frequency limit of the low loss integrated tuning structure in NbN is estimated as at least as 1.5 THz.
We report the development of a low noise SIS mixer aimed for 1 THz channel of the Caltech Airborne Submillimeter Interstellar Medium Investigations Receiver (CASIMIR), designed for the Stratospheric Observatory for Far Infrared Astronomy (SOFIA). The mixer uses Nb/Al-AlN/NbTiN SIS junctions with critical current density of about 45 kA/cm2. The junctions are shaped in order to optimize the suppression of the Josephson DC currents. We used a double slot planar antenna to couple the mixer chip with the telescope beam. The RF matching microcircuit is made using Nb and gold films. The mixer IF circuit is designed to cover 4-8 GHz band. The test receiver with the new mixer has the low noise operation in a 0.9-1.05 THz band. The minimum DSB receiver noise measured at 1 THz is 260 K (Y=1.64) , apparently the lowest reported up to date.