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

Josephson junction as F-band mixer-multiplier

V. D'yakov, V. Gubankov, A. Spitzin, Alexander N. Vystavkin

Published Jan 1, 1977• 2 citations
Publisher

Abstract

Properties of a niobium-niobium Josephson superconducting point contact (SPC) used as a mixer-multiplier have been investigated experimentally. Conversion of a microwave signal with frequency fs= 127 GHz into a signal with the intermediate frequency fif= 8.6 GHz has been obtained using heterodyne generators with frequencies fh= 136.68, 45, and 6.8 GHz, so that fif= nfh1,2,3 ....20- fswhere n = 1.2, 3.20 are heterodyne harmonics produced in the SPC. Dependences of the conversion efficiency (ηn) on the bias voltage, the heterodyne power and the heterodyne harmonics have been measured. In the case of the second and the twentieth harmonics, the best value of η20/η2was 0.25. This value is essentially higher than that obtained for the usual (conventional) semiconducting mixer. Performed experiments have demonstrated the perspective of utilization of SPC as a mixer-multiplier in millimeter and submillimeter wavebands.

DOI
10.1109/tmag.1977.1059438

Related papers

Frequency conversion with superconducting point contacts operating as oscillator-mixers and its application to the measurement of the linewidth of the Josephson current at very high frequency

G. Vernet, Robert Adde

The Josephson frequency conversion in the millimeter and submillimeter wave region is studied with superconducting Nb-Nb point contact junctions at 4.2 K, using the contact both as the local oscillator and the mixer with intermediate frequencies of 0.1 and 9.2 GHz. Frequency conversion signals are only detected in the latter case with a microwave receiver at 9.2 GHz in a range of Josephson frequencies between 145 and 1 600 GHz. The experiments with intermediate frequency fi of 0.1 GHz indicate for this small value of f i that the observed signals are not related to frequency conversion but noise effects. An analysis of the frequency conversion mechanism in a Josephson junction operated as an oscillator-mixer is proposed which includes the noise effects and also the feedback effects induced in a junction driven by a constant current source. We have then investigated the noise properties up to 450 GHz of superconducting point-contacts using the junction as an oscillator-mixer where the Josephson current is mixed with harmonics of an externally applied signal. The emitted intermediate frequency is detected at 9.2 GHz and its linewidth is measured. In the very high frequency range the dc quasiparticle current dominates in a Josephson weak-link and we compare the corresponding theoretical linewidth calculated by Scalapino with our experimental results.

Revue de Physique Appliquée•Jan 1, 1974•3 citations

Josephson frequency conversion in the range 145–1600 GHz with Nb–Nb superconducting point contacts used as oscillator-mixer

G. Vernet, Robert Adde

The Josephson frequency conversion in the millimeter and submillimeter wave region is studied with superconducting Nb–Nb point-contact junctions at 4.2 °K, using the contact both as the local oscillator and the mixer with intermediate frequencies of 0.1, 0.3, and 9.2 GHz. The point contact is in a nonresonant structure and fed by a constant current source: neither a strong rf coupling of the contact with a cavity nor a stabilizing shunt resistance was proved necessary. The direct observation of frequency conversion was performed with a microwave receiver at 9.2 GHz in a range of Josephson frequencies between 145 and 1600 GHz. The experiments with intermediate frequencies fi of 0.1 and 0.3 GHz indicate that conventional frequency conversion does not occur but that the observed signals are related to noise effects. An analysis of the frequency conversion mechanism in a Josephson junction operated as an oscillator-mixer is proposed which includes the noise effects and also the feedback effects induced in a junction driven by a constant current source. The results show that low-frequency current components are induced in the junction, which can give large spurious signals when small i.f. are used.

Journal of Applied Physics•Jun 1, 1974•13 citations

The Josephson junction as a mixer-multiplier for the centimeter and millimeter wave bands

M. V. Danileǐko, V. E. Derkach, A. M. Kostyshin +2 more

Recently there has been a marked upsurge in interest in the construction of multipliers and mixers for the SHF and IR regions. Of special interest in this respect are Josephson junctions fabricated from high-temperature superconductors. The present paper reports the results of experimental investigations of superconducting point junctions (SPJ) fabricated from the high-temperature superconductor Nb3Sn, and operating in regimes of frequency multiplication and mixing in the SHF spectral region. A controllable Nb3Sn Nb3 Sn SPJ that could be adjusted after being immersed in liquid helium was used in the experiments. The method of preparation of the SPJ was the same as the one that was employed in Ref. 1. The assembled experimental setup allowed the SPJ to be irradiated with three-centimeter and four-millimeter microwaves separately and simultaneously. The current-voltage characteristics (CVO) of the (tuned) SPJ were registered on an oscillograph and then recorded automatically at different DHF-power levels. The differential resistance RD = dU/dl of the junction as a function of mixing voltage UO was recorded with the aid of a lock-in amplifier2 co nstructed by us. All the measurements were carried out at the liquid-helium temperature. The SPJ in question had the following parameters: the critical current Ic = 0.1–2.5 rnA and the resistance in the normal state Rn = 0.1–10 Ω. When the SPJ was subjected to 8.9- and 87-GHz radiation separately, the CVC exhibited current steps at voltages corresponding to the fundamental frequency and the harmonics of the external radiation, as well as a sub harmonic structure. The multiplication of the fundamental frequency to 1 THz was recorded in the case of the irradiation of the SPJ by an 8.9–GHz signal and the registration of the dependence of RD on the mixing voltage U0. This differential CVC exhibited a subharmonic structure near the fundamental frequency at low SHF-power levels and near this frequency and its harmonics at higher levels. When the SPJ was irradiated by 87-GHz signals, the multiplication of the fundamental frequency of the signals to 2.2 THz was recorded on the differential CVC. The SHF-power dependence of the harmonics and subharmonics had an oscillatory character. The mechanism underlying the formation of the sub harmonic structure on the CVC of the SPJ can be explained if we take account of the effect of the action of the Josephson self-radiation on the junction itself.3 It should be noted that the manifestation of the Josephson properties in the frequency range ∼1 · 1012 Hz was observed for a SPJ with high Ic and Rn ⩾ 1 Ω. When the Nb3Sn–Nb3Sn SPJ was irradiated by two signals with frequencies 87 and 8.9 GHz simultaneously, there appeared near the steps for the 87-GHz signal , as the power of the 8.9-GHz signal was increased, steps corresponding to signals with frequencies equal to combinations of the two frequencies, i.e., (87m ± 8.9k)-Ghz combination steps appeared on the eve. Thus, the first experimental investigations of the multiplication and mixing of signals by Nb3Sn-Nb3Sn SPJ have shown that such SPJ operate quite well in regimes of mixing and multiplication of external SHF radiation.

Soviet Journal of Low Temperature Physics•Jun 1, 1980•0 citations

Superconducting Microwave Mixers Utilizing Josephson Junctions

A. DiNardo, E. Sard

Microwave superconducting mixers operating at 10–13 GHz utilizing Josephson junctions have been investigated analytically and experimentally. Measurements on mixer sensitivity were carried out at 13 GHz using waveguide-mounted experimental point-contact Josephson junctions at 4.2 K. Results showed sensitivities of −90 dBm/MHz (10−18 W/Hz) which included mismatch losses encountered in the waveguide structure. The Josephson junction mixing mechanism was analyzed on the basis of small-signal modulation of the staircase like dc I-V characteristics. It was shown that a small-signal microwave excitation results in an ac lateral shift of the regions between steps, such that: (a) Optimum Josephson mixing occurs halfway between steps. (b) Mixing occurs between all steps with maximum conversion efficiency between the zero and first step. (c) Predicted low conversion loss and possibly internal gain for a matched mixer. The analytical model was simulated by a digital computer and the behavior of the Josephson mixer predicted for various conditions of excitation. The model chosen for the analysis and the computer simulation is based on the simplest assumptions concerning bulk-formed Josephson junctions. In the laboratory an external local oscillator set 60 MHz below the signal frequency was used to induce the well-known step structure in the dc I-V characteristic of the point-contact Josephson junction. Mixing of the Lo and signal was found to occur between constant voltage steps in agreement with both analysis and computer simulation. The correctness of the model is demonstrated by the agreement between the theory and experiment.

Journal of Applied Physics•Jan 1, 1971•7 citations

Heterodyne reception at 891 GHz using a Josephson harmonic mixer and a microwave local oscillator

T. G. Blaney, D. J. E. Knight

The performance of Nb-Nb point-contact Josephson junction mixers was investigated experimentally with signals from a 891 GHz laser. The local oscillator (LO) was provided by the appropriate junction-generated harmonic of either a 74 or 99 GHz klystron. The intermediate frequency (IF) power varied linearly with signal power for signals less than 10 −5 to 10 −6 W. The optimum conversion loss (from 891 GHz to the IF) was not significantly different for the two klystron frequencies used: the lowest useful conversion loss for the whole mixing system including the signal input matching loss, was 42 (±3) dB. This is 10 dB greater than that observed with a 891 GHz laser LO and the same junction apparatus. Conversion loss of the mixer element alone was independent of IF with the latter varied up to 1·2 GHz. The noise at the output of the IF system was usually dominated by that of the transistor preamplifier with a noise temperature of about 500 K. Thus the input signal necessary to give a signal-to-noise ratio of one at the IF was equivalent to 10 −16 W Hz −1 of IF bandwidth. This mixing system, which can be significantly improved, forms the basis of a fully tunable heterodyne receiver for the submillimetre region.

Journal of Physics D Applied Physics•Sep 21, 1974•11 citations

Point-contact-type Josephson harmonic mixer for frequency measurement of far-infrared lasers

Yukinobu Miki, Eiichi Sakuma, Masanao Morimura

Point-contact-type Josephson junctions have been developed as a harmonic mixer to measure far-infrared (FIR) laser frequencies in a frequency chain up to the infrared region. The junctions were formed by mechanically pressing a niobium wire of 70 μm in diameter with a sharply etched tip against a niobium post of 2 mm in diameter. The voltage-current characteristics of the mixers were investigated under the irradiation of FIR lights from an optically pumped methyl-alcohol laser. The Shapiro steps for FIR lights up to 3.1 THz were observed. The mixing properties of the mixers were studied through harmonic mixing experiments of 50-GHz microwaves and the FIR lights up to the frequency of 3.1 THz. The conversion efficiency of the beat signals to the incident FIR power was found to vary as the — 4th power of the FIR frequency. From the mixing properties, the combination of the critical current Icof the junction and the product IcRnwhere Rnis the normal resistance of the junction, was found important to optimize the mixing performance.

IEEE Transactions on Instrumentation and Measurement•Jun 1, 1987•3 citations
Properties of a niobium-niobium Josephson superconducting point contact (SPC) used as a mixer-multiplier have been investigated experimentally. Conversion of a microwave signal with frequency fs= 127 GHz into a signal with the intermediate frequency fif= 8.6 GHz has been obtained using heterodyne generators with frequencies fh= 136.68, 45, and 6.8 GHz, so that fif= nfh1,2,3 ....20- fswhere n = 1.2, 3.20 are heterodyne harmonics produced in the SPC. Dependences of the conversion efficiency (ηn) on the bias voltage, the heterodyne power and the heterodyne harmonics have been measured. In the case of the second and the twentieth harmonics, the best value of η20/η2was 0.25. This value is essentially higher than that obtained for the usual (conventional) semiconducting mixer. Performed experiments have demonstrated the perspective of utilization of SPC as a mixer-multiplier in millimeter and submillimeter wavebands.
The Josephson frequency conversion in the millimeter and submillimeter wave region is studied with superconducting Nb-Nb point contact junctions at 4.2 K, using the contact both as the local oscillator and the mixer with intermediate frequencies of 0.1 and 9.2 GHz. Frequency conversion signals are only detected in the latter case with a microwave receiver at 9.2 GHz in a range of Josephson frequencies between 145 and 1 600 GHz. The experiments with intermediate frequency fi of 0.1 GHz indicate for this small value of f i that the observed signals are not related to frequency conversion but noise effects. An analysis of the frequency conversion mechanism in a Josephson junction operated as an oscillator-mixer is proposed which includes the noise effects and also the feedback effects induced in a junction driven by a constant current source. We have then investigated the noise properties up to 450 GHz of superconducting point-contacts using the junction as an oscillator-mixer where the Josephson current is mixed with harmonics of an externally applied signal. The emitted intermediate frequency is detected at 9.2 GHz and its linewidth is measured. In the very high frequency range the dc quasiparticle current dominates in a Josephson weak-link and we compare the corresponding theoretical linewidth calculated by Scalapino with our experimental results.
The Josephson frequency conversion in the millimeter and submillimeter wave region is studied with superconducting Nb–Nb point-contact junctions at 4.2 °K, using the contact both as the local oscillator and the mixer with intermediate frequencies of 0.1, 0.3, and 9.2 GHz. The point contact is in a nonresonant structure and fed by a constant current source: neither a strong rf coupling of the contact with a cavity nor a stabilizing shunt resistance was proved necessary. The direct observation of frequency conversion was performed with a microwave receiver at 9.2 GHz in a range of Josephson frequencies between 145 and 1600 GHz. The experiments with intermediate frequencies fi of 0.1 and 0.3 GHz indicate that conventional frequency conversion does not occur but that the observed signals are related to noise effects. An analysis of the frequency conversion mechanism in a Josephson junction operated as an oscillator-mixer is proposed which includes the noise effects and also the feedback effects induced in a junction driven by a constant current source. The results show that low-frequency current components are induced in the junction, which can give large spurious signals when small i.f. are used.
Recently there has been a marked upsurge in interest in the construction of multipliers and mixers for the SHF and IR regions. Of special interest in this respect are Josephson junctions fabricated from high-temperature superconductors. The present paper reports the results of experimental investigations of superconducting point junctions (SPJ) fabricated from the high-temperature superconductor Nb3Sn, and operating in regimes of frequency multiplication and mixing in the SHF spectral region. A controllable Nb3Sn Nb3 Sn SPJ that could be adjusted after being immersed in liquid helium was used in the experiments. The method of preparation of the SPJ was the same as the one that was employed in Ref. 1. The assembled experimental setup allowed the SPJ to be irradiated with three-centimeter and four-millimeter microwaves separately and simultaneously. The current-voltage characteristics (CVO) of the (tuned) SPJ were registered on an oscillograph and then recorded automatically at different DHF-power levels. The differential resistance RD = dU/dl of the junction as a function of mixing voltage UO was recorded with the aid of a lock-in amplifier2 co nstructed by us. All the measurements were carried out at the liquid-helium temperature. The SPJ in question had the following parameters: the critical current Ic = 0.1–2.5 rnA and the resistance in the normal state Rn = 0.1–10 Ω. When the SPJ was subjected to 8.9- and 87-GHz radiation separately, the CVC exhibited current steps at voltages corresponding to the fundamental frequency and the harmonics of the external radiation, as well as a sub harmonic structure. The multiplication of the fundamental frequency to 1 THz was recorded in the case of the irradiation of the SPJ by an 8.9–GHz signal and the registration of the dependence of RD on the mixing voltage U0. This differential CVC exhibited a subharmonic structure near the fundamental frequency at low SHF-power levels and near this frequency and its harmonics at higher levels. When the SPJ was irradiated by 87-GHz signals, the multiplication of the fundamental frequency of the signals to 2.2 THz was recorded on the differential CVC. The SHF-power dependence of the harmonics and subharmonics had an oscillatory character. The mechanism underlying the formation of the sub harmonic structure on the CVC of the SPJ can be explained if we take account of the effect of the action of the Josephson self-radiation on the junction itself.3 It should be noted that the manifestation of the Josephson properties in the frequency range ∼1 · 1012 Hz was observed for a SPJ with high Ic and Rn ⩾ 1 Ω. When the Nb3Sn–Nb3Sn SPJ was irradiated by two signals with frequencies 87 and 8.9 GHz simultaneously, there appeared near the steps for the 87-GHz signal , as the power of the 8.9-GHz signal was increased, steps corresponding to signals with frequencies equal to combinations of the two frequencies, i.e., (87m ± 8.9k)-Ghz combination steps appeared on the eve. Thus, the first experimental investigations of the multiplication and mixing of signals by Nb3Sn-Nb3Sn SPJ have shown that such SPJ operate quite well in regimes of mixing and multiplication of external SHF radiation.
Microwave superconducting mixers operating at 10–13 GHz utilizing Josephson junctions have been investigated analytically and experimentally. Measurements on mixer sensitivity were carried out at 13 GHz using waveguide-mounted experimental point-contact Josephson junctions at 4.2 K. Results showed sensitivities of −90 dBm/MHz (10−18 W/Hz) which included mismatch losses encountered in the waveguide structure. The Josephson junction mixing mechanism was analyzed on the basis of small-signal modulation of the staircase like dc I-V characteristics. It was shown that a small-signal microwave excitation results in an ac lateral shift of the regions between steps, such that: (a) Optimum Josephson mixing occurs halfway between steps. (b) Mixing occurs between all steps with maximum conversion efficiency between the zero and first step. (c) Predicted low conversion loss and possibly internal gain for a matched mixer. The analytical model was simulated by a digital computer and the behavior of the Josephson mixer predicted for various conditions of excitation. The model chosen for the analysis and the computer simulation is based on the simplest assumptions concerning bulk-formed Josephson junctions. In the laboratory an external local oscillator set 60 MHz below the signal frequency was used to induce the well-known step structure in the dc I-V characteristic of the point-contact Josephson junction. Mixing of the Lo and signal was found to occur between constant voltage steps in agreement with both analysis and computer simulation. The correctness of the model is demonstrated by the agreement between the theory and experiment.
The performance of Nb-Nb point-contact Josephson junction mixers was investigated experimentally with signals from a 891 GHz laser. The local oscillator (LO) was provided by the appropriate junction-generated harmonic of either a 74 or 99 GHz klystron. The intermediate frequency (IF) power varied linearly with signal power for signals less than 10 −5 to 10 −6 W. The optimum conversion loss (from 891 GHz to the IF) was not significantly different for the two klystron frequencies used: the lowest useful conversion loss for the whole mixing system including the signal input matching loss, was 42 (±3) dB. This is 10 dB greater than that observed with a 891 GHz laser LO and the same junction apparatus. Conversion loss of the mixer element alone was independent of IF with the latter varied up to 1·2 GHz. The noise at the output of the IF system was usually dominated by that of the transistor preamplifier with a noise temperature of about 500 K. Thus the input signal necessary to give a signal-to-noise ratio of one at the IF was equivalent to 10 −16 W Hz −1 of IF bandwidth. This mixing system, which can be significantly improved, forms the basis of a fully tunable heterodyne receiver for the submillimetre region.
Point-contact-type Josephson junctions have been developed as a harmonic mixer to measure far-infrared (FIR) laser frequencies in a frequency chain up to the infrared region. The junctions were formed by mechanically pressing a niobium wire of 70 μm in diameter with a sharply etched tip against a niobium post of 2 mm in diameter. The voltage-current characteristics of the mixers were investigated under the irradiation of FIR lights from an optically pumped methyl-alcohol laser. The Shapiro steps for FIR lights up to 3.1 THz were observed. The mixing properties of the mixers were studied through harmonic mixing experiments of 50-GHz microwaves and the FIR lights up to the frequency of 3.1 THz. The conversion efficiency of the beat signals to the incident FIR power was found to vary as the — 4th power of the FIR frequency. From the mixing properties, the combination of the critical current Icof the junction and the product IcRnwhere Rnis the normal resistance of the junction, was found important to optimize the mixing performance.