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 Journal of Quantum Electronics

Noise in SIS microwave mixers

Aldert van der Ziel

Published May 1, 1983• 2 citations
Publisher

Abstract

It is proposed that the noise in an SIS (superconductor-insulator-superconductor) microwave mixer is shot noise, and that it can be treated in a similar manner to the noise in Schottky barrier diodes. A noise temperature is defined, and how it can be optimized is indicated. An extension of the noise temperature concept of the source is used that makes noise temperatures additive at all frequencies.

DOI
10.1109/jqe.1983.1071944

Related papers

Constant output noise temperature of the superconducting quasiparticle mixer

Qing Ke, M. J. Feldman

The output noise temperature, rather than the standard input noise temperature, is shown to be the fundamental measure of the shot noise of the superconducting (SIS) quasiparticle mixer. This conclusion is based on extensive numerical computations of the properties of optimized SIS (superconductor-insulator-superconductor) receivers and also on analytic calculations with separate consideration of correlated and uncorrelated noise sources. The quantum theory of mixing is used to derive a simple analytic expression for the mixer output noise which is independent of frequency, and qualitatively explains the dependence of the output temperature on each of the receiver's operating parameters. The derivation leads to a novel understanding of the SIS mixer which, distinguishes between its correlated and uncorrelated noise sources. The authors predict T(receiver)=2*T(mixer) for many SIS receivers. Numerous experiments substantiate the analysis.>

IEEE Transactions on Applied Superconductivity•Mar 1, 1993•13 citations

SIS junction as a microwave noise source

Hirofumi Inoue, Takashi Noguchi, Kotaro Kohno

Cooled low noise amplifier (LNA) is used as the first or second component of receiver system in radio astronomy. It is developed all over the world to improve its noise. Noise temperature is one of the most important parameters of LNA because it governs the observation time. It is usually measured by inputting two reference signal which have different power each other and measuring the responses. For accuracy, the power of these reference signals is required to be close to the noise of the LNA. In the conventional method output of a Avalanche diode is attenuated to 1/100 by a cold attenuator and used as a reference signal. In this method the error caused by the attenuator and the cable between the Avalanche diode and LNA is too large (a few 10 %) and another accurate noise measurement method is required. In this research we propose a new method using Superconductor-Insulator-Superconductor junction (SIS) as a reference signal. When biased, SIS generates small shot noise that is proportional to the bias voltage so it can be used as a reference signal that make an accurate noise measurement possible (a few % error). First, SIS and SIS housing is designed and fabricated for the shot noise to transmit without any loss and reflection. Then, noise temperature of the LNA is measured by using the conventional method and SIS shot noise method and compared. As a result, there was difference and it was shown that the capacitance of SIS is one of the candidate cause.

Journal of Physics Conference Series•Jun 1, 2010•3 citations

Shot noise beyond the Tucker theory in niobium tunnel junction mixers

Pieter Dieleman, T. M. Klapwijk

The electrical and shot-noise characteristics of high-current-density niobium superconductor–insulator–superconductor (SIS) tunnel junctions suitable for heterodyne detection of THz radiation are studied. It is found that a significant part of the current at voltages V<2Δ/e is carried via barrier defects (pinholes). Due to the transport mechanism in these pinholes, the shot noise is considerably increased. The data presented clarify an often-observed discrepancy between measured and expected heterodyne mixer noise temperatures and predict a 25% increase in the receiver noise temperature of Nb SIS heterodyne detectors at 1 THz.

Applied Physics Letters•Mar 30, 1998•15 citations

Frequency dependence of quasiparticle mixers

W. C. Danchi, Edmund C. Sutton

An analysis of the frequency dependence of superconductor-insulator-normal (SIN) and superconductor-insulator-superconductor (SIS) quasiparticle mixers is presented. Power-law expressions for conversion loss and mixer shot-noise temperature for the double-sideband SIN mixer are derived from the Tucker theory for the case of a source conductance which is small compared to the conductance of the junction. For an ideal SIN tunnel junction at T=0 the mixer conversion efficiency is shown to decrease approximately linearly with frequency up to f=Δ/h. From f=Δ/h to 2Δ/h the conversion efficiency remains approximately constant, while above f=2Δ/h it rolls off as the inverse square of the frequency. Expressions for the shot-noise contribution to the mixer noise temperature are also derived. At frequencies up to f=Δ/h the noise temperature rises as the square root of the frequency. From f=Δ/h to f=2Δ/h the noise temperature of the mixer increases linearly with frequency, whereas above f=2Δ/h it rises as the cube of the frequency. Conversion efficiency and noise temperature are also calculated numerically for the SIN mixer. Good agreement is found between the frequency dependencies calculated analytically in the limit of small local oscillator power and the numerical calculations for optimal pumping. The frequency dependence of the nonideal SIS junction is also analyzed, and shown to yield similar results, with the characteristic frequencies Δ/h and 2Δ/h for a SIN mixer transformed into 2Δ/h and 4Δ/h, respectively. Expressions also are derived for the saturation power as a function of frequency.

Journal of Applied Physics•Dec 1, 1986•33 citations

Optimization of SIS mixer elements

Robert J. Mattauch

Superconductor-Insulator-Superconductor (SIS) quantum mixers provide an approach to millimeter wave mixing - potentially offering conversion gain, a low local oscillator power demand, and potential mixer noise temperatures near the quantum limit. The development of a reliable fabrication technology for producing such high quality SIS devices for mixer applications in radio astronomy is the focus of the work.

•Dec 1, 1985•0 citations

An SIS-mixer-based amplifier for multi-pixel heterodyne receivers

Yoshinori Uzawa, Takafumi Kojima, Yuto Kozuki +5 more

We are investigating a possible microwave amplifier with low noise and low power consumption at cryogenic temperature for large scale multi-pixel heterodyne superconductor-insulator-superconductor (SIS) receivers at millimeter and submillimeter wavelengths. We propose the use of SIS junctions as amplifier elements based on quasi-particle mixing. By connecting an SIS up-converter and an SIS down-converter in series with gain in both converters, a lownoise and low-power-consumption high-frequency amplifier can be obtained in principle. A proof-of-concept study has been made by configuring an amplifier with two Nb/Al-AlOx/Nb mixers in the 150-GHz band in a standard noise and gain measurement setup at 4 K with a microwave noise source as an input signal. We observed a maximum gain of more than 10 dB and a minimum noise temperature of less than 10 K, which suggests that our proposed SIS amplifier is capable for multi-pixel SIS receivers. On the other hand, we also observed a periodical behavior in frequency dependence of the measured noise temperature and gain due to a standing-wave effect between the two SIS mixers, which is a problem to be solved.

Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy XI•Dec 12, 2020•8 citations
It is proposed that the noise in an SIS (superconductor-insulator-superconductor) microwave mixer is shot noise, and that it can be treated in a similar manner to the noise in Schottky barrier diodes. A noise temperature is defined, and how it can be optimized is indicated. An extension of the noise temperature concept of the source is used that makes noise temperatures additive at all frequencies.
The output noise temperature, rather than the standard input noise temperature, is shown to be the fundamental measure of the shot noise of the superconducting (SIS) quasiparticle mixer. This conclusion is based on extensive numerical computations of the properties of optimized SIS (superconductor-insulator-superconductor) receivers and also on analytic calculations with separate consideration of correlated and uncorrelated noise sources. The quantum theory of mixing is used to derive a simple analytic expression for the mixer output noise which is independent of frequency, and qualitatively explains the dependence of the output temperature on each of the receiver's operating parameters. The derivation leads to a novel understanding of the SIS mixer which, distinguishes between its correlated and uncorrelated noise sources. The authors predict T(receiver)=2*T(mixer) for many SIS receivers. Numerous experiments substantiate the analysis.>
Cooled low noise amplifier (LNA) is used as the first or second component of receiver system in radio astronomy. It is developed all over the world to improve its noise. Noise temperature is one of the most important parameters of LNA because it governs the observation time. It is usually measured by inputting two reference signal which have different power each other and measuring the responses. For accuracy, the power of these reference signals is required to be close to the noise of the LNA. In the conventional method output of a Avalanche diode is attenuated to 1/100 by a cold attenuator and used as a reference signal. In this method the error caused by the attenuator and the cable between the Avalanche diode and LNA is too large (a few 10 %) and another accurate noise measurement method is required. In this research we propose a new method using Superconductor-Insulator-Superconductor junction (SIS) as a reference signal. When biased, SIS generates small shot noise that is proportional to the bias voltage so it can be used as a reference signal that make an accurate noise measurement possible (a few % error). First, SIS and SIS housing is designed and fabricated for the shot noise to transmit without any loss and reflection. Then, noise temperature of the LNA is measured by using the conventional method and SIS shot noise method and compared. As a result, there was difference and it was shown that the capacitance of SIS is one of the candidate cause.
The electrical and shot-noise characteristics of high-current-density niobium superconductor–insulator–superconductor (SIS) tunnel junctions suitable for heterodyne detection of THz radiation are studied. It is found that a significant part of the current at voltages V<2Δ/e is carried via barrier defects (pinholes). Due to the transport mechanism in these pinholes, the shot noise is considerably increased. The data presented clarify an often-observed discrepancy between measured and expected heterodyne mixer noise temperatures and predict a 25% increase in the receiver noise temperature of Nb SIS heterodyne detectors at 1 THz.
An analysis of the frequency dependence of superconductor-insulator-normal (SIN) and superconductor-insulator-superconductor (SIS) quasiparticle mixers is presented. Power-law expressions for conversion loss and mixer shot-noise temperature for the double-sideband SIN mixer are derived from the Tucker theory for the case of a source conductance which is small compared to the conductance of the junction. For an ideal SIN tunnel junction at T=0 the mixer conversion efficiency is shown to decrease approximately linearly with frequency up to f=Δ/h. From f=Δ/h to 2Δ/h the conversion efficiency remains approximately constant, while above f=2Δ/h it rolls off as the inverse square of the frequency. Expressions for the shot-noise contribution to the mixer noise temperature are also derived. At frequencies up to f=Δ/h the noise temperature rises as the square root of the frequency. From f=Δ/h to f=2Δ/h the noise temperature of the mixer increases linearly with frequency, whereas above f=2Δ/h it rises as the cube of the frequency. Conversion efficiency and noise temperature are also calculated numerically for the SIN mixer. Good agreement is found between the frequency dependencies calculated analytically in the limit of small local oscillator power and the numerical calculations for optimal pumping. The frequency dependence of the nonideal SIS junction is also analyzed, and shown to yield similar results, with the characteristic frequencies Δ/h and 2Δ/h for a SIN mixer transformed into 2Δ/h and 4Δ/h, respectively. Expressions also are derived for the saturation power as a function of frequency.
We are investigating a possible microwave amplifier with low noise and low power consumption at cryogenic temperature for large scale multi-pixel heterodyne superconductor-insulator-superconductor (SIS) receivers at millimeter and submillimeter wavelengths. We propose the use of SIS junctions as amplifier elements based on quasi-particle mixing. By connecting an SIS up-converter and an SIS down-converter in series with gain in both converters, a lownoise and low-power-consumption high-frequency amplifier can be obtained in principle. A proof-of-concept study has been made by configuring an amplifier with two Nb/Al-AlOx/Nb mixers in the 150-GHz band in a standard noise and gain measurement setup at 4 K with a microwave noise source as an input signal. We observed a maximum gain of more than 10 dB and a minimum noise temperature of less than 10 K, which suggests that our proposed SIS amplifier is capable for multi-pixel SIS receivers. On the other hand, we also observed a periodical behavior in frequency dependence of the measured noise temperature and gain due to a standing-wave effect between the two SIS mixers, which is a problem to be solved.