A High-Frequency DC SQUID Magnetic Sensor Design

This paper presents a SQUID-based quantum sensor for ultra-sensitive magnetic field detection, comprising a two-stage architecture utilizing the DC SQUID as a front-end sensor as well as for the Josephson Parametric Amplifier (JPA) in the second stage. The work details the circuit design and characteristics of the DC SQUID, introduces the challenges associated with high-frequency sensing, and analyzes the nonlinear behavior in the superconducting region crucial for ultra-sensitive detection. Furthermore, it demonstrates the gain enhancements achieved through the parametric amplifier and establishes a good match between device measurement results and the behavioral model.