Direct detection at submillimetre wavelengths using superconducting tunnel junctions

Withington, S.; Isaak, K.; Kovtonyuk, SA; Panhuyzen, R. A.; Klapwijk, T. M.

doi:10.1016/1350-4495(95)00058-5

Cited by 11 publications

(6 citation statements)

References 11 publications

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“…3, we plot the embedding impedance of the SIS device at different LO frequencies. For the experimental data, we recovered the embedding impedances from the pumped I-V curves, following [29], [30]. For the "HFSS" results, we simulated the reflection coefficient seen by the junction (S J,J ) using full-wave electromagnetic simulation software (ANSYS High Frequency Structural Simulator; HFSS) and then we calculated the embedding impedance using:…”

Section: Comparison Between Experimental and Simulated Resultsmentioning

confidence: 99%

Simulating the Behavior of a 230-GHz SIS Mixer Using Multitone Spectral Domain Analysis

Garrett

Tan

Boussaha

et al. 2019

IEEE Trans. THz Sci. Technol.

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We present a new software package, called QMix, for simulating the behavior of Superconductor / Insulator / Superconductor (SIS) mixers. The software uses a harmonic balance procedure to calculate the AC voltage across the SIS junction and multi-tone spectral domain analysis (MTSDA) to calculate the quasiparticle tunneling currents. This approach has two major advantages over other simulation techniques: (1) it can include an arbitrary number of higher-order harmonics, and(2) it can simulate the effect of multiple strong non-harmonic frequencies. This allows the QMix software to simulate a wide range of SIS mixer operation, including the effects of harmonics in the local-oscillator signal and gain saturation with respect to RF signal power.In this paper, we compare the simulated results from QMix to the measured performance of a 230 GHz SIS device, both to validate the software and to investigate the experimental data. To begin, we simulated the conversion gain of the mixer and we found excellent agreement with the experimental results. We were also able to recreate the broken photon step effect by adding higher-and lower-order harmonics to the LO signal. We then simulated a range of incident RF signal powers in order to calculate the gain saturation point. This is an important metric for SIS mixers because we require linear gain for reliable measurements and calibration. In the simulated results, we found both gain compression and gain expansion, which is consistent with other studies. Overall, these examples demonstrate that QMix is a powerful software package that will allow researchers to simulate the performance of SIS mixers, investigate experimental results and optimize mixer operation. We have made all of the QMix software open-source and we invite others to contribute to the project.

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Section: Comparison Between Experimental and Simulated Resultsmentioning

confidence: 99%

Simulating the Behavior of a 230-GHz SIS Mixer Using Multitone Spectral Domain Analysis

Garrett

Tan

Boussaha

et al. 2019

IEEE Trans. THz Sci. Technol.

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“…4, we estimate that a 5% reduction in the voltage-to-current conversion factor occurs for a normalized signal amplitude of about 0.6, corresponding to 17 nW of available rf signal power. 10 Hence good linearity can be achieved even with high levels of rf power, which shows that this mode of operation is suitable for making antenna pattern measurements. This level of rf power is comparable to the power that causes the responsivity of a SIS direct detector to fall by about 5%.…”

Section: Parametermentioning

confidence: 93%

Theoretical and numerical analysis of very high harmonic superconducting tunnel junction mixers

Kittara

Withington

Yassin

2007

Journal of Applied Physics

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We describe a procedure for modeling the nonlinear, quantum-mechanical behavior of very high harmonic superconductor-insulator-superconductor (SIS) mixers. A typical mixer is pumped by a strong microwave source at 10–15GHz, which causes high-harmonic (20–40) currents to flow, any one of which can be used as a local oscillator to downconvert a submillimeter-wave signal to a low microwave frequency, 1–8GHz. This mode of operation is attractive for measuring the beam patterns of conventional SIS mixers, because only a single submillimeter-wave source is needed. We conducted simulations using the 20th harmonic of a 13.5GHz microwave source, downconverting a 271.4GHz signal to a 1.4GHz intermediate frequency. These simulations clearly show that linear downconversion can be achieved even for relatively high levels of rf signal power; although, care is needed when choosing the operating point. The patterns of behavior seen in the simulations are in remarkable agreement with recently published experimental results.

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“…With these parameters and the tuning circuit dimensions, the mixer would have given good performance between 600-700 GHz. However, the embedding impedance recovery [17], [18] performed to find the position of the resonance frequency and close inspection of the pumped IV curves, indicated that the tuning was shifted to below 600 GHz. Considering that the normal resistance of the junction came below the design value of 20 , the low tuning frequency could be explained by a larger than designed tunnel junction area.…”

Section: Mixer Assembly and Fabricationmentioning

confidence: 98%

A 650 GHz Unilateral Finline SIS Mixer Fed by a Multiple Flare-Angle Smooth-Walled Horn

Tan

Yassin

Grimes

et al. 2012

IEEE Trans. THz Sci. Technol.

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We report the design and successful operation of an superconductor-insulator-superconductor (SIS) mixer operating near the superconducting gap of niobium. A key feature of this design is the employment of a unilateral finline taper to transform the waveguide modes to microstrip signals. This transition is easy to design since it can be rigorously modeled, and also easy to fabricate being a single-layer structure. We will show that unilateral finline mixers have important advantages at THz frequencies since they exhibit wideband operation at both radio frequency (RF) and intermediate frequency (IF), allow elegant on-chip integration of the mixer circuits and result in an extremely simple mixer block that does not require a backshort or any mechanical tuners. The mixer we describe below is fed by a multiple flare-angle smooth-walled horn which exhibits beam pattern characteristic comparable to the conventional corrugated horn and yet is much easier to fabricate.In this paper, we shall present a brief discussion of the testing of the multiple flare-angle horn and detailed description of the design and testing of the mixer, covering 100 GHz bandwidth centered at 650 GHz. In particular, we will present full electromagnetic design description of the mixer chip including the superconducting effects, and the heterodyne properties of the mixer using quantum mixing theory. Mixer performance tests that we carried out from 595 to 702 GHz gave a best receiver noise temperature of 145 K at 600 GHz, corrected for a 75 m beam splitter.Finally, we performed a thorough analysis of the mixer performance, comparing the experimental results with theoretical models. Our investigation demonstrated that unilateral finline mixers fed by a multiple flare-angle horn can yield performance comparable to conventional designs, hence are suitable for large format mixer array at THz frequencies.

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Direct detection at submillimetre wavelengths using superconducting tunnel junctions

Cited by 11 publications

References 11 publications

Simulating the Behavior of a 230-GHz SIS Mixer Using Multitone Spectral Domain Analysis

Simulating the Behavior of a 230-GHz SIS Mixer Using Multitone Spectral Domain Analysis

Theoretical and numerical analysis of very high harmonic superconducting tunnel junction mixers

A 650 GHz Unilateral Finline SIS Mixer Fed by a Multiple Flare-Angle Smooth-Walled Horn

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