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 Magnetics

SIS mixer analysis using a scale model

M. J. Feldman, S.-K. Pan, Anthony R. Kerr, A. Davidson

Published May 1, 1983• 28 citations
Publisher

Abstract

In this paper measurements on a 115 GHz SIS mixer are shown to be in good quantitative agreement with the predictions of the quantum theory of mixing. A 40 × scale model of the mixer block was used to determine the experimental embedding impedances.
DOI
10.1109/tmag.1983.1062406

Related papers

Comparison of measured and predicted performance of a SIS waveguide mixer at 345 GHz

Cornelia E. Honingh, G. Delange, M. M. T. M. Dierichs +5 more

The measured gain and noise of a SIS waveguide mixer at 345 GHz have been compared with theoretical values, calculated from the quantum mixer theory using a three port model. As a mixing element, we use a series array of two Nb-Al2O3-Nb SIS junctions. The area of each junction is 0.8 sq microns and the normal state resistance is 52 omega. The embedding impedance of the mixer has been determined from the pumped DC-IV curves of the junction and is compared to results from scale model measurements (105 x). Good agreement was obtained. The measured mixer gain, however, is a factor of 0.45 plus or minus 0.5 lower than the theoretical predicted gain. The measured mixer noise temperature is a factor of 4-5 higher than the calculated one. These discrepancies are independent on pump power and are valid for a broad range of tuning conditions.

•Jan 1, 1992•1 citation

Embedding Impedance Measurements for mm-Wave SIS Mixers

Antti V. Räisänen, William R. McGrath, Denis Crété +1 more

Several scaled models have been used to determine the contributions of various waveguide mount parameters to the embedding impedance of a mm-wave superconductor-insulator-superconductor (SIS) mixer. Measured effects of waveguide height, substrate orientation and width, junction location, lead inductance and RF-filter impedance are presented and discussed.

European Microwave Conference (EuMC)•Oct 1, 1985•0 citations

Quantum limited quasiparticle mixers at 100 GHz

C. A. Mears, Qing Hu, P. L. Richards +3 more

Accurate measurements of the noise and gain of superconducting-insulating-superconducting (SIS) mixers using small-area (1 mu m/sup 2/) Ta/Ta/sub 2/O/sub 5//Pb/sub 0.9/Bi/sub 0.1/ tunnel junctions were made. The authors measured an added mixer noise of 0.61+or-0.31 quanta at 95.0 GHz, which is within 25% of the quantum limit of 0.5 quanta. Detailed comparison between theoretical predictions of the quantum theory of mixing has been carried out, and noise and gain have been experimentally measured. The shapes of the I-V curves pumped at the upper and lower sideband frequencies were used to deduce values of the embedding admittances at these frequencies. Using these admittances, the mixer noise and gain predicted by quantum theory are in excellent agreement with experiment.

IEEE Transactions on Magnetics•Mar 1, 1991•20 citations

Quantum-limited quasiparticle mixers at 100 GHz

C. A. Mears, Qing Hu, Paul L. Richards +3 more

Accurate measurements have been made of the noise and gain of superconducting-insulating- superconducting (SIS) mixers employing small-area (1 micrometers 2) Ta/Ta2O5/Pb0.9Bi0.1 tunnel junctions. The authors have measured an added mixer noise of 0.61 +/- 0.31 quanta at 95.0 GHz, which is within 25% of the quantum limit of 0.5 quanta. A detailed comparison is made between theoretical predictions of the quantum theory of mixing and experimentally measured noise and gain. The authors used the shapes of I-V curves pumped at the upper and lower sideband frequencies to deduce values of the embedding admittances at these frequencies. Using these admittances, the mixer noise and gain predicted by quantum theory are in excellent agreement with experiment.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Jul 1, 1991•2 citations

Extensive test of the three-port quantum mixer theory on 345 GHz superconductor-insulator-superconductor mixers

Cornelia E. Honingh, J. J. Wezelman, M. M. T. M. Dierichs +4 more

Predictions of the three-port model of the quantum theory of mixing are compared with measured results on 345 GHz superconductor-insulator-superconductor waveguide mixers. Single Nb-Al2O3-Nb tunnel junctions or two or four identical junctions in series are used as mixing elements. Two different waveguide mixerblocks, one with two tuners and another with one tuner, are used. In addition a single junction with integrated tuning stub is analyzed. Embedding impedances are obtained from fits to the pumped I-V curves for all three types of mixing elements. In all cases the dependence of mixer conversion and mixer noise on bias voltage, pump power, and embedding impedance is well described by the three-port model. The measured mixer gain is lower than the calculated gain by a factor of 0.35–0.65, independent of the type of mixer. The use of an additional integrated tuning element does not change this factor. It is concluded that an excess noise power equivalent with a blackbody source of 40–65 K must be added to the mixer noise to account for the absolute value of the observed noise power.

Journal of Applied Physics•Oct 1, 1993•9 citations

A general numerical analysis of the superconducting quasiparticle mixer

R.G. Hicks, M. J. Feldman, Anthony R. Kerr

Virtually all analyses of the superconductor-insulator-superconductor (SIS) quasiparticle mixer have employed the quantum theory of mixing in its three-frequency approximate form. This approximation is valid only in the limit of very large junction capacitance. For finite capacitance, these analyses may be seriously in error. To remedy this, a computer program has been developed which uses the quantum theory of mixing in its most general form, treating the large-signal properties of the mixer in the time domain. The terminating impedances at the harmonics of the local oscillator frequency and their sidebands can be arbitrary. Using this analysis, the effect of finite junction capacitance on one SIS mixer's performance is described. This gives an insight into the range of validity of the three-frequency model.

IEEE Transactions on Magnetics•Mar 1, 1985•15 citations
The measured gain and noise of a SIS waveguide mixer at 345 GHz have been compared with theoretical values, calculated from the quantum mixer theory using a three port model. As a mixing element, we use a series array of two Nb-Al2O3-Nb SIS junctions. The area of each junction is 0.8 sq microns and the normal state resistance is 52 omega. The embedding impedance of the mixer has been determined from the pumped DC-IV curves of the junction and is compared to results from scale model measurements (105 x). Good agreement was obtained. The measured mixer gain, however, is a factor of 0.45 plus or minus 0.5 lower than the theoretical predicted gain. The measured mixer noise temperature is a factor of 4-5 higher than the calculated one. These discrepancies are independent on pump power and are valid for a broad range of tuning conditions.
Accurate measurements of the noise and gain of superconducting-insulating-superconducting (SIS) mixers using small-area (1 mu m/sup 2/) Ta/Ta/sub 2/O/sub 5//Pb/sub 0.9/Bi/sub 0.1/ tunnel junctions were made. The authors measured an added mixer noise of 0.61+or-0.31 quanta at 95.0 GHz, which is within 25% of the quantum limit of 0.5 quanta. Detailed comparison between theoretical predictions of the quantum theory of mixing has been carried out, and noise and gain have been experimentally measured. The shapes of the I-V curves pumped at the upper and lower sideband frequencies were used to deduce values of the embedding admittances at these frequencies. Using these admittances, the mixer noise and gain predicted by quantum theory are in excellent agreement with experiment.
Accurate measurements have been made of the noise and gain of superconducting-insulating- superconducting (SIS) mixers employing small-area (1 micrometers 2) Ta/Ta2O5/Pb0.9Bi0.1 tunnel junctions. The authors have measured an added mixer noise of 0.61 +/- 0.31 quanta at 95.0 GHz, which is within 25% of the quantum limit of 0.5 quanta. A detailed comparison is made between theoretical predictions of the quantum theory of mixing and experimentally measured noise and gain. The authors used the shapes of I-V curves pumped at the upper and lower sideband frequencies to deduce values of the embedding admittances at these frequencies. Using these admittances, the mixer noise and gain predicted by quantum theory are in excellent agreement with experiment.
Predictions of the three-port model of the quantum theory of mixing are compared with measured results on 345 GHz superconductor-insulator-superconductor waveguide mixers. Single Nb-Al2O3-Nb tunnel junctions or two or four identical junctions in series are used as mixing elements. Two different waveguide mixerblocks, one with two tuners and another with one tuner, are used. In addition a single junction with integrated tuning stub is analyzed. Embedding impedances are obtained from fits to the pumped I-V curves for all three types of mixing elements. In all cases the dependence of mixer conversion and mixer noise on bias voltage, pump power, and embedding impedance is well described by the three-port model. The measured mixer gain is lower than the calculated gain by a factor of 0.35–0.65, independent of the type of mixer. The use of an additional integrated tuning element does not change this factor. It is concluded that an excess noise power equivalent with a blackbody source of 40–65 K must be added to the mixer noise to account for the absolute value of the observed noise power.
Virtually all analyses of the superconductor-insulator-superconductor (SIS) quasiparticle mixer have employed the quantum theory of mixing in its three-frequency approximate form. This approximation is valid only in the limit of very large junction capacitance. For finite capacitance, these analyses may be seriously in error. To remedy this, a computer program has been developed which uses the quantum theory of mixing in its most general form, treating the large-signal properties of the mixer in the time domain. The terminating impedances at the harmonics of the local oscillator frequency and their sidebands can be arbitrary. Using this analysis, the effect of finite junction capacitance on one SIS mixer's performance is described. This gives an insight into the range of validity of the three-frequency model.