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 Applied Superconductivity

Flux-Driven Josephson Parametric Amplifiers Based on an RF SQUID and DC SQUID in Keysight ADS

Keith Krause, Michael C. Hamilton, Mark L. Adams

Published Dec 19, 2025• 0 citations
Publisher

Abstract

Josephson parametric amplifiers (JPAs) have become an important component of superconducting applications. Simulating these circuits is vital for optimizing their performance, including their gain and stability. Previously, simulating JPAs has been inefficient due to the limits of using SPICE-based simulators that work in the time domain. JPAs are better suited to frequency domain simulations over a broad frequency range and parameter space. We present JPA simulations using the recently released flux-aware Josephson junction (JJ) and inductor models in Keysight Advanced Design Systems (ADS). We simulate two different flux-driven JPAs: one based on an RF SQUID, and another based on a DC SQUID. We efficiently run harmonic balance simulations over a wide range of circuit parameters. We compare the use of RF and DC SQUIDs in these JPAs by analyzing their simulation results. This work provides a foundation for future SQUID-based JPA simulations in Keysight ADS.

DOI
10.1109/tasc.2025.3645151

Related papers

Modeling Flux-Quantizing Josephson Junction Circuits in Keysight ADS

Ofer Naaman, Mohamed H. Awida, T. White +4 more

We introduce Josephson junction and inductor models in Keysight Advanced Design System that feature an auxiliary flux port, and facilitate the expression of flux quantization conditions in simulation of superconducting microwave circuits. We present several examples that illustrate our methodology for constructing flux-quantizing circuits, including dc- andrf-SQUIDs, tunable couplers, and parametric amplifiers using superconducting nonlinear asymmetric inductive element and rf-SQUID arrays. We perform dc, S-parameter, and harmonic balance simulations to validate our models and methods against theory and published experimental results.

arXiv:2408.07861•IEEE Transactions on Applied Superconductivity•Jan 15, 2025•13 citations

Simulation of a flux-pumped Josephson parametric amplifier with a detailed SQUID model using the harmonic balance method

Kaiyong He, Genting Dai, Qing Yu +4 more

Abstract This work presents an analysis of a flux-pumped Josephson parametric amplifier (JPA) with a detailed superconducting quantum interference device (SQUID) model, using the harmonic balance (HB) method in Keysight’s Advanced Design System. The model is built using the generalized resistively shunted junction model of a Josephson junction and the quantization condition of a SQUID, incorporating the effects of the geometric inductance and parasitic parameters. This approach is used to simulate the behavior of an unmatched lumped element JPA and an impedance-matched JPA, showing the necessity of the detailed SQUID model for the simulation of a broadband JPA by comparison with the results based on a widely used, simplified model. Gain profiles obtained from the approach are consistent with existing experiments in the literature, with reasonable accuracy. Due to the HB method, the simulation is of high efficiency, making it feasible to sweep and optimize parameters. This provides a useful method for the analysis of Josephson parametric amplification and the design of a JPA.

Superconductor Science and Technology•Jan 18, 2023•7 citations

Flux-driven Josephson parametric amplifiers: Hysteretic flux response and nondegenerate gain measurements

Stefan Pogorzalek, Kirill G. Fedorov, L. Zhong +11 more

Josephson parametric amplifiers (JPA) have become key devices in quantum science and technology with superconducting circuits. In particular, they can be utilized as quantum-limited amplifiers or as a source of squeezed microwave fields. Here, we report on the detailed measurements of five flux-driven JPAs, three of them exhibiting a hysteretic dependence of the resonant frequency versus the applied magnetic flux. We model the measured characteristics by numerical simulations based on the two-dimensional potential landscape of the dc superconducting quantum interference devices (dc-SQUID), which provide the JPA nonlinearity, for a finite screening parameter $β_\mathrm{L}\,{>}\,0$ and demonstrate excellent agreement between the numerical results and the experimental data. Furthermore, we study the nondegenerate response of different JPAs and accurately describe the experimental results with our theory.

arXiv:1609.09041•Sep 28, 2016•9 citations

Flux-Pumped Josephson Travelling-Wave Parametric Amplifiers Based on Bi-SQUID Cells

Renat A. Yusupov, Lyudmila V. Filippenko, Daniil E. Bazulin +5 more

We have proposed a new design of the Josephson traveling-wave parametric amplifier (JTWPA) capable of providing much higher spurious-free dynamic range (SFDR). For this purpose, we substitute dc SQUIDs for bi-SQUIDs in the used artificial signal transmission line driven by external travelling-wave magnetic flux. The increase of SFDR follows from the increased linearity domain of the phase-current relation in bi-SQUID as compared to dc SQUID. Optimal parameters for bi-SQUIDs have been determined. The first version of JTWPA was modeled to be fabricated using niobium process.

IEEE Transactions on Applied Superconductivity•Nov 26, 2021•11 citations

A Superconducting Quantum Interference Device Model for the Design and Optimization of Quantum-Limited Microwave Amplifiers in Harmonic Balance Simulators

Alírio Boaventura

We present a dc superconducting quantum interference device (dc-SQUID) model for the design and optimization of quantum-limited parametric amplifiers. These devices are critical for superconducting quantum computing and do not currently have comprehensive models that designers can use to simulate their circuits in standard circuit simulators. Our model has been implemented and tested in the Advanced Design Systems (ADS) simulation software and validated against analytical predictions.

URSI Atlantic Radio Science Conference•May 29, 2022•2 citations

Flux-Driven Josephson Parametric Amplifier Fabricated Using the Nb/AlO x /Nb Trilayer Process

Gahyun Choi, Bokyung Kim, Jiman Choi +3 more

In this paper, we report a flux-driven Josephson parametric amplifier (JPA) fabricated using the Nb/AlOx/Nb Josephson junction process. The JPA consists of a parallel-plate type coupling capacitor and quarter-wavelength resonator terminated with a DC-SQUID. We adopt a simple process using well-established Nb trilayer technology. The overall configuration time of the Nb-based JPA can be shortened by measuring resonant frequency and its bias dependence in liquid helium. Amplification of the pre-tested device was demonstrated, showing a gain of 20 dB in a −3 dB bandwidth of 17 MHz in a 10 mK dilution fridge.

IEEE Transactions on Applied Superconductivity•Apr 11, 2023•2 citations
Josephson parametric amplifiers (JPAs) have become an important component of superconducting applications. Simulating these circuits is vital for optimizing their performance, including their gain and stability. Previously, simulating JPAs has been inefficient due to the limits of using SPICE-based simulators that work in the time domain. JPAs are better suited to frequency domain simulations over a broad frequency range and parameter space. We present JPA simulations using the recently released flux-aware Josephson junction (JJ) and inductor models in Keysight Advanced Design Systems (ADS). We simulate two different flux-driven JPAs: one based on an RF SQUID, and another based on a DC SQUID. We efficiently run harmonic balance simulations over a wide range of circuit parameters. We compare the use of RF and DC SQUIDs in these JPAs by analyzing their simulation results. This work provides a foundation for future SQUID-based JPA simulations in Keysight ADS.
We introduce Josephson junction and inductor models in Keysight Advanced Design System that feature an auxiliary flux port, and facilitate the expression of flux quantization conditions in simulation of superconducting microwave circuits. We present several examples that illustrate our methodology for constructing flux-quantizing circuits, including dc- andrf-SQUIDs, tunable couplers, and parametric amplifiers using superconducting nonlinear asymmetric inductive element and rf-SQUID arrays. We perform dc, S-parameter, and harmonic balance simulations to validate our models and methods against theory and published experimental results.
Abstract This work presents an analysis of a flux-pumped Josephson parametric amplifier (JPA) with a detailed superconducting quantum interference device (SQUID) model, using the harmonic balance (HB) method in Keysight’s Advanced Design System. The model is built using the generalized resistively shunted junction model of a Josephson junction and the quantization condition of a SQUID, incorporating the effects of the geometric inductance and parasitic parameters. This approach is used to simulate the behavior of an unmatched lumped element JPA and an impedance-matched JPA, showing the necessity of the detailed SQUID model for the simulation of a broadband JPA by comparison with the results based on a widely used, simplified model. Gain profiles obtained from the approach are consistent with existing experiments in the literature, with reasonable accuracy. Due to the HB method, the simulation is of high efficiency, making it feasible to sweep and optimize parameters. This provides a useful method for the analysis of Josephson parametric amplification and the design of a JPA.
Josephson parametric amplifiers (JPA) have become key devices in quantum science and technology with superconducting circuits. In particular, they can be utilized as quantum-limited amplifiers or as a source of squeezed microwave fields. Here, we report on the detailed measurements of five flux-driven JPAs, three of them exhibiting a hysteretic dependence of the resonant frequency versus the applied magnetic flux. We model the measured characteristics by numerical simulations based on the two-dimensional potential landscape of the dc superconducting quantum interference devices (dc-SQUID), which provide the JPA nonlinearity, for a finite screening parameter βL > 0β_\mathrm{L}\,{>}\,0βL​>0 and demonstrate excellent agreement between the numerical results and the experimental data. Furthermore, we study the nondegenerate response of different JPAs and accurately describe the experimental results with our theory.
We have proposed a new design of the Josephson traveling-wave parametric amplifier (JTWPA) capable of providing much higher spurious-free dynamic range (SFDR). For this purpose, we substitute dc SQUIDs for bi-SQUIDs in the used artificial signal transmission line driven by external travelling-wave magnetic flux. The increase of SFDR follows from the increased linearity domain of the phase-current relation in bi-SQUID as compared to dc SQUID. Optimal parameters for bi-SQUIDs have been determined. The first version of JTWPA was modeled to be fabricated using niobium process.
In this paper, we report a flux-driven Josephson parametric amplifier (JPA) fabricated using the Nb/AlOx/Nb Josephson junction process. The JPA consists of a parallel-plate type coupling capacitor and quarter-wavelength resonator terminated with a DC-SQUID. We adopt a simple process using well-established Nb trilayer technology. The overall configuration time of the Nb-based JPA can be shortened by measuring resonant frequency and its bias dependence in liquid helium. Amplification of the pre-tested device was demonstrated, showing a gain of 20 dB in a −3 dB bandwidth of 17 MHz in a 10 mK dilution fridge.