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G N Goltsman - One of the best experts on this subject based on the ideXlab platform.
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Temperature dependence of the receiver Noise Temperature and if bandwidth of superconducting hot electron bolometer mixers
Superconductor Science and Technology, 2014Co-Authors: Wen Zhang, Wei Miao, Sheng-cai Shi, J Q Zhong, D J Hayton, N Vercruyssen, J R Gao, G N GoltsmanAbstract:In this paper we study the Temperature dependence of the receiver Noise Temperature and IF Noise bandwidth of superconducting hot electron bolometer (HEB) mixers. Three superconducting NbN HEB devices of different transition Temperatures (T-c) are measured at 0.85 THz and 1.4 THz at different bath Temperatures (T-bath) between 4 K and 9 K. Measurement results demonstrate that the receiver Noise Temperature of superconducting NbN HEB devices is nearly constant for T-bath/T-c, less than 0.8, which is consistent with the simulation based on a distributed hot-spot model. In addition, the IF Noise bandwidth appears independent of T-bath/T-c, indicating the dominance of phonon cooling in the investigated HEB devices.
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Noise Temperature and local oscillator power requirement of nbn phonon cooled hot electron bolometric mixers at terahertz frequencies
Applied Physics Letters, 1998Co-Authors: P Yagoubov, G N Goltsman, Matthias Kroug, H Merkel, E Kollberg, S I Svechnikov, E. M. GershenzonAbstract:In this letter, the Noise performance of NbN-based phonon-cooled hot electron bolometric quasioptical mixers is investigated in the 0.55–1.1 THz frequency range. The best results of the double-sideband (DSB) Noise Temperature are: 500 K at 640 GHz, 600 K at 750 GHz, 850 K at 910 GHz, and 1250 K at 1.1 THz. The water vapor in the signal path causes significant contribution to the measured receiver Noise Temperature around 1.1 THz. The devices are made from 3-nm-thick NbN film on high-resistivity Si and integrated with a planar spiral antenna on the same substrate. The in-plane dimensions of the bolometer strip are typically 0.2×2 μm. The amount of local oscillator power absorbed in the bolometer is less than 100 nW.
J R Gao - One of the best experts on this subject based on the ideXlab platform.
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Temperature dependence of the receiver Noise Temperature and if bandwidth of superconducting hot electron bolometer mixers
Superconductor Science and Technology, 2014Co-Authors: Wen Zhang, Wei Miao, Sheng-cai Shi, J Q Zhong, D J Hayton, N Vercruyssen, J R Gao, G N GoltsmanAbstract:In this paper we study the Temperature dependence of the receiver Noise Temperature and IF Noise bandwidth of superconducting hot electron bolometer (HEB) mixers. Three superconducting NbN HEB devices of different transition Temperatures (T-c) are measured at 0.85 THz and 1.4 THz at different bath Temperatures (T-bath) between 4 K and 9 K. Measurement results demonstrate that the receiver Noise Temperature of superconducting NbN HEB devices is nearly constant for T-bath/T-c, less than 0.8, which is consistent with the simulation based on a distributed hot-spot model. In addition, the IF Noise bandwidth appears independent of T-bath/T-c, indicating the dominance of phonon cooling in the investigated HEB devices.
Wen Zhang - One of the best experts on this subject based on the ideXlab platform.
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Dependence of Noise Temperature of Superconducting HEB Mixers on Frequency and Bath Temperature
2018 International Conference on Microwave and Millimeter Wave Technology (ICMMT), 2018Co-Authors: Kangmin Zhou, Daowei Wang, Wei Miao, Wen ZhangAbstract:A log-spiral antenna coupled 0.1-1.5 THz NbN superconducting HEB mixer has been characterized by measuring its double sideband (DSB) receiver Noise Temperature (Trec) from 0.22 THz to 1.44 THz and at 4 K-7 K bath Temperatures. The measured uncorrected Trec is 800 K, 800 K, 750 K and 850 K at 0.22 THz, 0.55 THz, 0.85 THz and 1.44 THz respectively. The optimal bias voltage seems independent to the frequency and bath Temperature. The bath-Temperature dependence of Noise Temperature has also been investigated, the bath Temperature has limited effect on the Noise Temperature when it is operated below its transition Temperature. A similar frequency response of corrected mixer Noise Temperature has been observed at 4 K and 7 K bath Temperature, which indicates the RF coupling efficiency of planar spiral antenna of HEB mixer.
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Temperature dependence of the receiver Noise Temperature and if bandwidth of superconducting hot electron bolometer mixers
Superconductor Science and Technology, 2014Co-Authors: Wen Zhang, Wei Miao, Sheng-cai Shi, J Q Zhong, D J Hayton, N Vercruyssen, J R Gao, G N GoltsmanAbstract:In this paper we study the Temperature dependence of the receiver Noise Temperature and IF Noise bandwidth of superconducting hot electron bolometer (HEB) mixers. Three superconducting NbN HEB devices of different transition Temperatures (T-c) are measured at 0.85 THz and 1.4 THz at different bath Temperatures (T-bath) between 4 K and 9 K. Measurement results demonstrate that the receiver Noise Temperature of superconducting NbN HEB devices is nearly constant for T-bath/T-c, less than 0.8, which is consistent with the simulation based on a distributed hot-spot model. In addition, the IF Noise bandwidth appears independent of T-bath/T-c, indicating the dominance of phonon cooling in the investigated HEB devices.
A. I. Elantiev - One of the best experts on this subject based on the ideXlab platform.
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Noise Temperature limit of a superconducting hot‐electron bolometer mixer
Applied Physics Letters, 1996Co-Authors: Boris S. Karasik, A. I. ElantievAbstract:A theoretical analysis for the Noise Temperature of a low‐Temperature hot‐electron superconducting mixer has been presented. The contribution of both Johnson Noise and electron Temperature fluctuations has been evaluated. The theoretical limit of the single‐side band Noise Temperature of the device due to the intrinsic Noise mechanisms has been estimated to be as low as 20–40 K, depending on the film material. The corresponding Noise bandwidth can be as large as 2–3 GHz, for a device with the electron‐phonon cooling mechanism. An improvement of the sensitivity is not necessarily followed by a decrease of the mixer conversion gain bandwidth.
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Noise Temperature limit of a superconducting hot electron bolometer mixer
Applied Physics Letters, 1996Co-Authors: Boris S. Karasik, A. I. ElantievAbstract:A theoretical analysis for the Noise Temperature of a low‐Temperature hot‐electron superconducting mixer has been presented. The contribution of both Johnson Noise and electron Temperature fluctuations has been evaluated. The theoretical limit of the single‐side band Noise Temperature of the device due to the intrinsic Noise mechanisms has been estimated to be as low as 20–40 K, depending on the film material. The corresponding Noise bandwidth can be as large as 2–3 GHz, for a device with the electron‐phonon cooling mechanism. An improvement of the sensitivity is not necessarily followed by a decrease of the mixer conversion gain bandwidth.
John Clarke - One of the best experts on this subject based on the ideXlab platform.
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A Numerical Treatment of the Rf SQUID: II. Noise Temperature
Lawrence Berkeley National Laboratory, 2008Co-Authors: Reinhold Kleiner, Dieter Koelle, John ClarkeAbstract:A Numerical Treatment of the Rf SQUID: II. Noise Temperature Reinhold Kleiner 1 , Dieter Koelle 1 and John Clarke 2 Physikalisches Institut-Experimentalphysik II, Universitat Tubingen, 72076 Tubingen, Germany Department of Physics, University of California, Berkeley, California 94720-7300, and Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 E-mail: kleiner@uni-tuebingen.de We investigate rf SQUIDs (Superconducting QUantum Interference Devices), coupled to a resonant input circuit, a readout tank circuit and a preamplifier, by numerically solving the corresponding Langevin equations and optimizing model parameters with respect to Noise Temperature. We also give approximate analytic solutions for the Noise Temperature, which we reduce to parameters of the SQUID and the tank circuit in the absence of the input circuit. The analytic solutions agree with numerical simulations of the full circuit to within 10%, and are similar to expressions used to calculate the Noise Temperature of dc SQUIDs. The best device performance is obtained when β L ≡ 2 π LI 0 / Φ 0 is 0.6 - 0.8; L is the SQUID inductance, I 0 the junction critical current and Φ 0 the flux quantum. For a tuned input circuit we find an optimal Noise Temperature T N , opt ≈ 3 Tf / f c , where T, f and f c denote Temperature, signal frequency and junction characteristic frequency, respectively. This value is only a factor of 2 larger than the optimal Noise Temperatures obtained by approximate analytic theories carried out previously in the limit β L
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A Numerical Treatment of the rf SQUID: II. Noise Temperature
Journal of Low Temperature Physics, 2007Co-Authors: Reinhold Kleiner, Dieter Koelle, John ClarkeAbstract:We investigate rf SQUIDs (Superconducting QUantum Interference Devices), coupled to a resonant input circuit, a readout tank circuit and a preamplifier, by numerically solving the corresponding Langevin equations and optimizing model parameters with respect to Noise Temperature. We also give approximate analytic solutions for the Noise Temperature, which we reduce to parameters of the SQUID and the tank circuit in the absence of the input circuit. The analytic solutions agree with numerical simulations of the full circuit to within 10%, and are similar to expressions used to calculate the Noise Temperature of dc SQUIDs. The best device performance is obtained when {beta}{sub L}{prime} {triple_bond} 2{pi}LI{sub 0}/{Phi}{sub 0} is 0.6-0.8; L is the SQUID inductance, I{sub 0} the junction critical current and F{sub 0} the flux quantum. For a tuned input circuit we find an optimal Noise Temperature T{sub N,opt} {approx} 3Tf/f{sub c}, where T, f and f{sub c} denote Temperature, signal frequency and junction characteristic frequency, respectively. This value is only a factor of 2 larger than the optimal Noise Temperatures obtained by approximate analytic theories carried out previously in the limit {beta}{sub L}{prime} << 1. We study the dependence of the Noise Temperature on various model parameters, and give examples using realistic device parameters of the extent to which the intrinsic Noise Temperature can be realized experimentally
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A Numerical Treatment of the rf SQUID: II. Noise Temperature
Journal of Low Temperature Physics, 2007Co-Authors: Reinhold Kleiner, Dieter Koelle, John ClarkeAbstract:We investigate rf SQUIDs (Superconducting QUantum Interference Devices), coupled to a resonant input circuit, a readout tank circuit and a preamplifier, by numerically solving the corresponding Langevin equations. The quantity of interest is the Noise Temperature T N . We use an analytical expression T N0,opt, which is already optimized for the parameters of the input circuit, and vary the model parameters of the remaining circuit to minimize T N0,opt. We also compare T N0,opt to numerical simulations of the full circuit and find good agreement. The best device performance is obtained when β′ L ≡2π LI 0/Φ 0 is in the range 0.5–0.9; L is the SQUID inductance, I 0 the junction critical current and Φ 0 the flux quantum. For a tuned input circuit we find an optimal Noise Temperature T N0,opt≈3Tf/f c , where T, f and f c denote Temperature, signal frequency and junction characteristic frequency, respectively. This value is close to the optimal Noise Temperatures obtained by approximate analytical theories carried out previously in the limit β′ L ≲1. We study the dependence of T N0,opt on various model parameters away from their optimum values, and often find much lower values of T N0,opt than predicted by the analytical theory. We finally discuss implications for devices that can be implemented experimentally.