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

International Conference on Submillimeter Waves and Their Applications

Conversion Efficiency and Noise Measurements of SIS Array Mixers

Herman van Kempen, William R. McGrath, P. L. Richards, A. D. Smith, R. Harris, Frances L. Lloyd

Published Dec 1, 1981• 3 citations
Publisher

Abstract

Quasiparticle heterodyne mixers which use series arrays [1] of Pb-alloy SIS tunnel junctions have been tested at 36 GHz. These arrays each showed a conversion loss of approximately 5dB. Single-sideband noise temperatures of 9.8 ± 5K, 34 ± 12 K, and 85 ± 25 K were measured for 1, 10 and 50 junction arrays respectively. Significantly increased saturation levels were observed for the 10 and 50 junction arrays.

DOI
10.1109/icswa.1981.9335104

Related papers

Accurate noise measurements of superconducting quasiparticle array mixers

William R. McGrath, Antti V. Räisänen, P. L. Richards +2 more

We have constructed a 30-40 GHz test apparatus which allows us to measure the noise temperatures of SIS mixers with an accuracy of better than ±1K. This is a factor of six improvement over earlier measurements. The most accurate measurement made thus far of a mixer which uses a single Pb-alloy junction yielded Tm= 9.2 ± 0.9 K; and mixer gain: Gm= 0.240 ± 0.005. In addition, SIS mixers employing arrays of N = 1, 5, 10, 25, and 50 tunnel junctions in series have been tested. The input power required to saturate the array mixers was found to increase as N2and the gain and noise temperature of the array mixers were independent of N.

IEEE Transactions on Magnetics•Mar 1, 1985•37 citations

Performance of Arrays of SIS Junctions in Heterodyne Mixers

Denis Crété, William R. McGrath, P. L. Richards

We have made a systematic experimental study of the performance of millimeter-wave quasiparticle heterodyne mixers which use arrays of SIS tunnel junctions. Sets of arrays with N =1, 5, 10, 25, and 50 junctions in series were fabricated by photolithography. All of the arrays in a given set were made on a single silicon wafer so that their response time parameter omega/sub S/R/sub N/C would be the same. Junction areas were scaled so that the total impedance was the same for each array in a set. Sets of arrays from four wafers with values of omega/sub S/R/sub N/C ranging from 2.6 to 13 were evaluated in mixers at 33 and 36 GHz. These measurements showed that the signal power required to saturate the mixers varies as N/sup 2/ and that the conversion efficiency is nearly independent of N for all values of omega/sub S/R/sub N/C. The mixer noise temperature is independent of N for large values of omega/sub S/R/sub N/C. Therefore, the dynamic range of an SIS quasiparticle mixer can increase in proportion to N/sup 2/. For small values of as omega/sub S/R/sub N/C, however, the mixer noise increases systematically with N. This correlation suggests that the junction capacitance affects the coupling between junctions that can contribute to the noise.

IEEE Transactions on Microwave Theory and Techniques•Apr 1, 1987•24 citations

Performance of heterodyne mixers using arrays of SIS junctions

Denis Crété, William R. McGrath, P. L. Richards +1 more

The SIS quasiparticle tunnel junction has been demonstrated to be the most sensitive mixing element for millimeter wave receivers [1,2]. Conversion gain greater than 1 and noise temperature approaching the quantum limit [3,4] has been observed. The required local oscillator power, which can be as small as 10−8W, leads to a low saturation threshold for these mixers [5,6]. The practical benefits, including higher saturation power, of using series arrays are sufficiently important that a substantial number of experiments using arrays have been reported [2,6,7,8,9]. It has not been clear, however, whether there has been any sacrifice in mixer conversion efficiency (gain) or noise. We present a systematic experimental investigation of mixing performance in series arrays of N junctions, where N = 1, 5, 10, 25 and 50.

International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz)•Dec 1, 1985•0 citations

Arrays of superconducting tunnel junctions as low-noise 10-GHz mixers

S. Rudner, T. Claeson

Quasiparticle mixing (biasing at the gap voltage) was studied in arrays of small Pb-O-Pb tunnel junctions. Coherent mixing at 9 GHz gave a conversion loss as low as −5.8 dB and a single sideband mixer noise temperature of 10–40 K. The optimal conversion efficiency was obtained where the bias current microwave response was maximal. The arrays of junctions were rugged, and gave a good impedance match to external circuitry.

Applied Physics Letters•May 15, 1979•49 citations

Low noise SIS receiver performance using Pb alloy tunnel junctions

Steven R. Davies, Leslie T. Little

A receiver noise temperature of 61 K (DSB) has been measured for a superconductor–insulator–superconductor (SIS) heterodyne receiver operating at 232 GHz, the lowest value reported to date for such a receiver employing a lead alloy junction. Analysis of the losses of the receiver components yields mixer noise temperature and conversion loss, Tm = 24 K and Lm = 2.1 dB (DSB). These are compared with predictions based on 3-port quantum mixer theory, made using the measured characteristics of the junction and an equivalent circuit for the waveguide mixer mount deduced from scaled modelling experiments.

IEE Proceedings - Microwaves Antennas and Propagation•Jan 1, 1998•0 citations

Quasiparticle Tunnel Junctions for MM-Wave Detection

K. H. Gundlach, S. Takada, M. Zahn +1 more

The paper describes preparation and properties of Pb/In-oxide-Pb(Bi) tunnel junctions for SIS quasiparticle mixer. The effect of repeated thermal cycling on the junction I-V characteristic has been investigated. The present laboratory model of a 70 GHz heterodyne receiver with these devices has a single sideband conversion efficiency just above the classical limit and a mixer noise temperature well below 100 K.

International Conference on Submillimeter Waves and Their Applications•Dec 1, 1981•0 citations
Quasiparticle heterodyne mixers which use series arrays [1] of Pb-alloy SIS tunnel junctions have been tested at 36 GHz. These arrays each showed a conversion loss of approximately 5dB. Single-sideband noise temperatures of 9.8 ± 5K, 34 ± 12 K, and 85 ± 25 K were measured for 1, 10 and 50 junction arrays respectively. Significantly increased saturation levels were observed for the 10 and 50 junction arrays.
We have constructed a 30-40 GHz test apparatus which allows us to measure the noise temperatures of SIS mixers with an accuracy of better than ±1K. This is a factor of six improvement over earlier measurements. The most accurate measurement made thus far of a mixer which uses a single Pb-alloy junction yielded Tm= 9.2 ± 0.9 K; and mixer gain: Gm= 0.240 ± 0.005. In addition, SIS mixers employing arrays of N = 1, 5, 10, 25, and 50 tunnel junctions in series have been tested. The input power required to saturate the array mixers was found to increase as N2and the gain and noise temperature of the array mixers were independent of N.
We have made a systematic experimental study of the performance of millimeter-wave quasiparticle heterodyne mixers which use arrays of SIS tunnel junctions. Sets of arrays with N =1, 5, 10, 25, and 50 junctions in series were fabricated by photolithography. All of the arrays in a given set were made on a single silicon wafer so that their response time parameter omega/sub S/R/sub N/C would be the same. Junction areas were scaled so that the total impedance was the same for each array in a set. Sets of arrays from four wafers with values of omega/sub S/R/sub N/C ranging from 2.6 to 13 were evaluated in mixers at 33 and 36 GHz. These measurements showed that the signal power required to saturate the mixers varies as N/sup 2/ and that the conversion efficiency is nearly independent of N for all values of omega/sub S/R/sub N/C. The mixer noise temperature is independent of N for large values of omega/sub S/R/sub N/C. Therefore, the dynamic range of an SIS quasiparticle mixer can increase in proportion to N/sup 2/. For small values of as omega/sub S/R/sub N/C, however, the mixer noise increases systematically with N. This correlation suggests that the junction capacitance affects the coupling between junctions that can contribute to the noise.
The SIS quasiparticle tunnel junction has been demonstrated to be the most sensitive mixing element for millimeter wave receivers [1,2]. Conversion gain greater than 1 and noise temperature approaching the quantum limit [3,4] has been observed. The required local oscillator power, which can be as small as 10−8W, leads to a low saturation threshold for these mixers [5,6]. The practical benefits, including higher saturation power, of using series arrays are sufficiently important that a substantial number of experiments using arrays have been reported [2,6,7,8,9]. It has not been clear, however, whether there has been any sacrifice in mixer conversion efficiency (gain) or noise. We present a systematic experimental investigation of mixing performance in series arrays of N junctions, where N = 1, 5, 10, 25 and 50.
A receiver noise temperature of 61 K (DSB) has been measured for a superconductor–insulator–superconductor (SIS) heterodyne receiver operating at 232 GHz, the lowest value reported to date for such a receiver employing a lead alloy junction. Analysis of the losses of the receiver components yields mixer noise temperature and conversion loss, Tm = 24 K and Lm = 2.1 dB (DSB). These are compared with predictions based on 3-port quantum mixer theory, made using the measured characteristics of the junction and an equivalent circuit for the waveguide mixer mount deduced from scaled modelling experiments.