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 Access

Characterizing Scattering Parameters of Superconducting Quantum Integrated Circuits at Milli-Kelvin Temperatures

Manoj Stanley, Sebastian E. de Graaf, T. Hönigl-Decrinis, T. Lindström, Nick Ridler

Published Jan 1, 2022• 18 citations
Publisher

Abstract

Designing large-scale superconducting quantum circuits involves complex microwave engineering to minimize loss, spurious reflections, and signal crosstalk. Essential for engineering more complex circuits is precise knowledge of devices’ microwave performance, which can be characterized by measuring its calibrated scattering parameters (S-parameters) at mK temperatures. In this work, we introduce a full 2-port calibrated S-parameter measurement setup which can characterize superconducting quantum integrated circuits and other RF integrated circuits operating at mK temperatures. The design and architecture of the measurement system consisting of in-house developed microwave calibration unit (MCU) housing the newly designed cryogenic calibration standards and the device under test (DUT) is discussed in detail. The measurement setup is then used to demonstrate the first calibrated S-parameter measurements of an in-house developed superconducting qubit integrated circuit at mK temperature.

DOI
10.1109/access.2022.3169787

Related papers

Design of Microwave Calibration Standards for Characterising S-Parameters of Quantum Integrated Circuits at Millikelvin Temperatures

Manoj Stanley, Sebastian E. de Graaf, T. Lindström +3 more

In the field of quantum information science, superconducting quantum integrated circuits are operated at millikelvin temperatures inside dilution refrigerators. The microwave performance of such non-connectorised devices can be characterised by measuring their calibrated S-parameters. The design of high-quality microwave standards is essential to achieve accurate calibration. In this work we describe the architecture of a full 2-port S-parameter measurement set-up for use at millikelvin temperatures along with the microwave calibration unit. The design of the standards for use in the calibration unit at millikelvin temperatures is described and verified using electromagnetic simulation and measurements. The suitability of the standards is verified by characterising a commercial attenuator as a test device.

European Microwave Conference (EuMC)•Apr 4, 2022•2 citations

Characterising Scattering Parameters of Coaxial Microwave Devices at Milli-kelvin Temperatures for Quantum Computing Technologies

Manoj Stanley, Sang-Hee Shin, James Skinner +2 more

Quantum computing technologies utilise microwave components and interfaces at cryogenic temperatures during operation. This paper describes an S-parameter measurement system to characterise coaxial microwave devices at temperatures down to tens of milli-kelvin. The measurement system is calibrated using a Thru-reflect-line technique utilising a coaxial air-dielectric transmission line as the reference impedance standard. Various coaxial microwave devices having a wide range of reflection and transmission coefficient values are measured at both room temperature and mK temperature to investigate the calibration performance and understand the various error sources in the measurements.

European Microwave Conference (EuMC)•Sep 19, 2023•8 citations

Broadband calibrated scattering parameters characterization of a superconducting quantum interference device amplifier

Leonardo Ranzani, Lafe Spietz, José Aumentado

In this work, we characterize the 2-port scattering parameters of a superconducting quantum interference device amplifier at ∼20 mK over several gigahertz of bandwidth. The measurement reference plane is positioned on a 6.25 Ω microstrip line situated directly at the input and output of the device by means of a thru-reflect-line cryogenic calibration procedure. From the scattering parameters, we derive the device available power gain, isolation, and input impedance over the 2–8 GHz range. This measurement methodology provides a path towards designing wide-band matching circuits for low impedance superconducting amplifiers operating at dilution refrigerator temperatures.

Applied Physics Letters•Jul 8, 2013•14 citations

Broadband Coaxial S-Parameter Measurements for Cryogenic Quantum Technologies

Sang-Hee Shin, Manoj Stanley, James Skinner +2 more

Development of RF and microwave metrology capabilities at cryogenic temperatures is critical for the development of high-performance microwave devices to facilitate commercialization of cryogenic quantum technologies. This article presents a broadband microwave S-parameter calibration scheme suitable for cryogenic environments operating at temperatures down to tens of milli-kelvin (mK). The technique is based on a weighted multi-line thru-reflect-line (TRL) calibration approach and is demonstrated using coaxial air line calibration standards. One-and two-port microwave devices commonly used in cryogenic quantum computing applications, a cryogenic 50$~\Omega$matched load and a cryogenic 6 dB attenuator, were measured. The measured results at mK temperatures indicate that when combined with calibration standards of appropriate electrical length, the weighted multi-line TRL calibration scheme allows broadband frequency coverage compared to conventional TRL calibration schemes utilizing a single line standard. The mechanical and electrical properties of the line standards at mK temperatures were investigated and discussed. These findings establish the feasibility of utilizing multiple off-the-shelf coaxial air lines to enhance the frequency range of calibrations at mK temperatures.

IEEE Transactions on Microwave Theory and Techniques•Oct 17, 2023•16 citations

Validating S‐parameter measurements of RF integrated circuits at milli‐Kelvin temperatures

Manoj Stanley, S. J. Park, Sebastian E. de Graaf +3 more

Abstract Techniques to precisely characterise RF components at milli‐Kelvin temperatures support the development of quantum computing systems utilising these components. In this work, an S‐parameter measurement setup to characterise RF integrated circuits at milli‐Kelvin temperatures has been proposed and for the first time, the S‐parameter measurements at milli‐Kelvin temperatures have been validated using two independent calibration techniques, thereby providing more confidence in measurements. The techniques are demonstrated experimentally by comparing and validating calibrated S‐parameter measurements of a cryogenic attenuator integrated circuits at milli‐Kelvin temperatures.

Electronics Letters•Jun 18, 2022•17 citations

RF and microwave metrology for quantum computing – recent developments at the UK’s National Physical Laboratory

Manoj Stanley, Xiaobang Shang, Murat Celep +9 more

Abstract Development of large-scale quantum computing systems will require radio frequency (RF) and microwave technologies operating reliably at cryogenic temperatures down to tens of milli-Kelvin (mK). The quantum bits in the most promising quantum computing technologies such as the superconducting quantum computing are designed using principles of microwave engineering and operated using microwave signals. The control, readout, and coupling of qubits are implemented using a network of microwave components operating at various temperature stages. To ensure reliable operation of quantum computing systems, it is critical to ensure optimal performance of these microwave components and qubits at their respective operating temperatures, which can be as low as mK temperatures. It is, therefore, critical to understand the microwave characteristics of waveforms, components, circuits, networks, and systems at cryogenic temperatures. The UK’s National Physical Laboratory (NPL) is focussed on developing new microwave measurement capabilities through the UK’s National Quantum Technologies Programme to address various microwave test and measurement challenges in quantum computing. This includes the development of various measurement capabilities to characterize the microwave performance of quantum and microwave devices and substrate materials at cryogenic temperatures. This paper summarizes the roadmap of activities at NPL to address these microwave metrology challenges in quantum computing.

International Journal of Microwave and Wireless Technologies•Apr 25, 2024•8 citations
Designing large-scale superconducting quantum circuits involves complex microwave engineering to minimize loss, spurious reflections, and signal crosstalk. Essential for engineering more complex circuits is precise knowledge of devices’ microwave performance, which can be characterized by measuring its calibrated scattering parameters (S-parameters) at mK temperatures. In this work, we introduce a full 2-port calibrated S-parameter measurement setup which can characterize superconducting quantum integrated circuits and other RF integrated circuits operating at mK temperatures. The design and architecture of the measurement system consisting of in-house developed microwave calibration unit (MCU) housing the newly designed cryogenic calibration standards and the device under test (DUT) is discussed in detail. The measurement setup is then used to demonstrate the first calibrated S-parameter measurements of an in-house developed superconducting qubit integrated circuit at mK temperature.
In the field of quantum information science, superconducting quantum integrated circuits are operated at millikelvin temperatures inside dilution refrigerators. The microwave performance of such non-connectorised devices can be characterised by measuring their calibrated S-parameters. The design of high-quality microwave standards is essential to achieve accurate calibration. In this work we describe the architecture of a full 2-port S-parameter measurement set-up for use at millikelvin temperatures along with the microwave calibration unit. The design of the standards for use in the calibration unit at millikelvin temperatures is described and verified using electromagnetic simulation and measurements. The suitability of the standards is verified by characterising a commercial attenuator as a test device.
Quantum computing technologies utilise microwave components and interfaces at cryogenic temperatures during operation. This paper describes an S-parameter measurement system to characterise coaxial microwave devices at temperatures down to tens of milli-kelvin. The measurement system is calibrated using a Thru-reflect-line technique utilising a coaxial air-dielectric transmission line as the reference impedance standard. Various coaxial microwave devices having a wide range of reflection and transmission coefficient values are measured at both room temperature and mK temperature to investigate the calibration performance and understand the various error sources in the measurements.
In this work, we characterize the 2-port scattering parameters of a superconducting quantum interference device amplifier at ∼20 mK over several gigahertz of bandwidth. The measurement reference plane is positioned on a 6.25 Ω microstrip line situated directly at the input and output of the device by means of a thru-reflect-line cryogenic calibration procedure. From the scattering parameters, we derive the device available power gain, isolation, and input impedance over the 2–8 GHz range. This measurement methodology provides a path towards designing wide-band matching circuits for low impedance superconducting amplifiers operating at dilution refrigerator temperatures.
Development of RF and microwave metrology capabilities at cryogenic temperatures is critical for the development of high-performance microwave devices to facilitate commercialization of cryogenic quantum technologies. This article presents a broadband microwave S-parameter calibration scheme suitable for cryogenic environments operating at temperatures down to tens of milli-kelvin (mK). The technique is based on a weighted multi-line thru-reflect-line (TRL) calibration approach and is demonstrated using coaxial air line calibration standards. One-and two-port microwave devices commonly used in cryogenic quantum computing applications, a cryogenic 50 Ω~\Omega Ωmatched load and a cryogenic 6 dB attenuator, were measured. The measured results at mK temperatures indicate that when combined with calibration standards of appropriate electrical length, the weighted multi-line TRL calibration scheme allows broadband frequency coverage compared to conventional TRL calibration schemes utilizing a single line standard. The mechanical and electrical properties of the line standards at mK temperatures were investigated and discussed. These findings establish the feasibility of utilizing multiple off-the-shelf coaxial air lines to enhance the frequency range of calibrations at mK temperatures.
Abstract Techniques to precisely characterise RF components at milli‐Kelvin temperatures support the development of quantum computing systems utilising these components. In this work, an S‐parameter measurement setup to characterise RF integrated circuits at milli‐Kelvin temperatures has been proposed and for the first time, the S‐parameter measurements at milli‐Kelvin temperatures have been validated using two independent calibration techniques, thereby providing more confidence in measurements. The techniques are demonstrated experimentally by comparing and validating calibrated S‐parameter measurements of a cryogenic attenuator integrated circuits at milli‐Kelvin temperatures.
Abstract Development of large-scale quantum computing systems will require radio frequency (RF) and microwave technologies operating reliably at cryogenic temperatures down to tens of milli-Kelvin (mK). The quantum bits in the most promising quantum computing technologies such as the superconducting quantum computing are designed using principles of microwave engineering and operated using microwave signals. The control, readout, and coupling of qubits are implemented using a network of microwave components operating at various temperature stages. To ensure reliable operation of quantum computing systems, it is critical to ensure optimal performance of these microwave components and qubits at their respective operating temperatures, which can be as low as mK temperatures. It is, therefore, critical to understand the microwave characteristics of waveforms, components, circuits, networks, and systems at cryogenic temperatures. The UK’s National Physical Laboratory (NPL) is focussed on developing new microwave measurement capabilities through the UK’s National Quantum Technologies Programme to address various microwave test and measurement challenges in quantum computing. This includes the development of various measurement capabilities to characterize the microwave performance of quantum and microwave devices and substrate materials at cryogenic temperatures. This paper summarizes the roadmap of activities at NPL to address these microwave metrology challenges in quantum computing.