High-T<sub>c</sub>micro and nano-constrictions modeling: hot spot approach for DC characteristics and HEB THz mixer performance

Ladret, Romain G.; Dégardin, Annick; Kreisler, Alain

doi:10.1088/1742-6596/507/4/042020

Cited by 2 publications

(5 citation statements)

References 10 publications

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“…This also comforts the validity of the non-homogeneous LO power distribution, a key point of this paper. With the usual homogeneous LO power assumption [16], we obtain, for the same constriction as in Table II (750 GHz), T DSB = 1600 K and G = −13 dB, at optimal P LO = 35 μW (i.e., only ∼25% of P LO would be efficient in the hot spot mixing process). Finally, our model only considers the input THz frequency dependence, and not the intermediate frequency (IF) cutoff, estimated at f esc ≈ 1/(2πτ esc ) = 63 MHz in our case.…”

Section: B Mixer Noise Temperature and Conversion Gainmentioning

confidence: 78%

“…Besides, as already mentioned in [25], and considered in [12], [16], the bias current dependence of the critical temperature-with critical exponent γ-has also been accounted for in this study.…”

Section: Antenna To Constriction Impedance Matchingmentioning

confidence: 98%

“…1, and write the thermal exchange in the device as governed by the heat equations pertaining to the electrons (1) and phonons (2) of the YBCO film, bearing indices e and p, respectively. In contrast with our initial formulation in [12], we introduce a full treatment of the phonon temperature and consider, as in [16], that it is not possible to neglect the phonon heat diffusion in high-T C materials (second order derivative in (2)). Moreover, we introduce a local source term in (1) to express the nonuniformity of both DC and RF power dissipation along the constriction length.…”

Section: A Electron and Phonon Heat Equationsmentioning

confidence: 99%

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YBCO-Constriction Hot Spot Modeling: DC and RF Descriptions for HEB THz Mixer Noise Temperature and Conversion Gain

Ladret¹,

Kreisler²,

Dégardin³

2014

IEEE Trans. Appl. Supercond.

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International audienceTo investigate the THz mixing performance of YBCO hot electron bolometers (HEB), the influence of the local oscillator (LO) radiofrequency (RF) radiation has been considered in detail. As opposed to the usual hot spot modeling approach, where the LO power is assumed to be uniformly distributed over the HEB constriction length, a uniform RF current has been assumed. The local electron temperature – as obtained by solving the coupled electron and phonon thermal reservoir equations – could then be used to determine the local YBCO complex resistivity, hence the locally dissipated LO power. Besides, the use of a modified two-fluid description allowed to determine the RF-dependent temperature shift (∼ −1% THz−1) and broadening (∼ +20% THz−1) of the resistive transition. Finally, the impedance matching to the THz antenna was considered. For a typical constriction, the conversion loss and noise temperature TDSB were computed, with TDSB ∝ exp(0.32f) behavior up to 2.5 THz

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Section: B Mixer Noise Temperature and Conversion Gainmentioning

confidence: 78%

Section: Antenna To Constriction Impedance Matchingmentioning

confidence: 98%

Section: A Electron and Phonon Heat Equationsmentioning

confidence: 99%

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YBCO-Constriction Hot Spot Modeling: DC and RF Descriptions for HEB THz Mixer Noise Temperature and Conversion Gain

Ladret¹,

Kreisler²,

Dégardin³

2014

IEEE Trans. Appl. Supercond.

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“…The aim of this article is twofold. First, we shall provide a complete and detailed description of the YBCO HEB model and extend the results of [25][26][27] up to 4 THz. We shall also compare our modeling results in terms of the device performance as a THz heterodyne mixer with the few experimental data available for YBCO HEB mixers, which can be found in the literature.…”

Section: Introductionmentioning

confidence: 94%

“…First developed for low T C HEBs [24], this so-called "hot spot" modeling was further applied to high T C devices [25]. The YBCO HEB model then evolved to include more realistic descriptions, such as the phonon temperature spatial dependence T p (x) [26] and the operating radio frequency (RF) influence on the shape of the resistance vs. temperature superconducting transition [27].…”

Section: Introductionmentioning

confidence: 99%

THz Mixing with High-TC Hot Electron Bolometers: A Performance Modeling Assessment for Y-Ba-Cu-O Devices

et al. 2019

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Hot electron bolometers (HEB) made from high-TC superconducting YBa2Cu3O7–x (YBCO) oxide nano-constrictions are promising THz mixers, due to their expected wide bandwidth, large mixing gain, and low intrinsic noise. The challenge for YBCO resides, however, in the chemical reactivity of the material and the related aging effects. In this paper, we model and simulate the frequency dependent performance of YBCO HEBs operating as THz mixers. We recall first the main hypotheses of our hot spot model taking into account both the RF frequency effects in the YBCO superconducting transition and the nano-constriction impedance at THz frequencies. The predicted performance up to 4 THz is given in terms of double sideband noise temperature TDSB and conversion gain G. At 2.5 THz for instance, TDSB  1000 K and G 6 dB could be achieved at 12.5 W local oscillator power. We then consider a standoff target detection scheme and examine the feasibility with YBCO devices. For instance, detection at 3 m through cotton cloth in passive imaging mode could be readily achieved in moderate humidity conditions with 10 K resolution.

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High-T_cmicro and nano-constrictions modeling: hot spot approach for DC characteristics and HEB THz mixer performance

Cited by 2 publications

References 10 publications

YBCO-Constriction Hot Spot Modeling: DC and RF Descriptions for HEB THz Mixer Noise Temperature and Conversion Gain

YBCO-Constriction Hot Spot Modeling: DC and RF Descriptions for HEB THz Mixer Noise Temperature and Conversion Gain

THz Mixing with High-TC Hot Electron Bolometers: A Performance Modeling Assessment for Y-Ba-Cu-O Devices

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High-Tcmicro and nano-constrictions modeling: hot spot approach for DC characteristics and HEB THz mixer performance

Cited by 2 publications

References 10 publications

YBCO-Constriction Hot Spot Modeling: DC and RF Descriptions for HEB THz Mixer Noise Temperature and Conversion Gain

YBCO-Constriction Hot Spot Modeling: DC and RF Descriptions for HEB THz Mixer Noise Temperature and Conversion Gain

THz Mixing with High-TC Hot Electron Bolometers: A Performance Modeling Assessment for Y-Ba-Cu-O Devices

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High-T_cmicro and nano-constrictions modeling: hot spot approach for DC characteristics and HEB THz mixer performance