Circuits and method for biasing magnetic flux through a superconducting quantum interference array

A circuit includes a Superconducting Quantum Interference Array (SQIF), a bias circuit, and a coil. The SQIF generates an output voltage that is a transfer function of the magnetic flux perpendicularly passing through the SQIF. An external magnetic field and a bias magnetic field supply the magnetic flux. The bias circuit generates a bias current for biasing the SQIF at an operating point. The coil generates the bias magnetic field through the SQIF from the bias current of the bias circuit. The bias magnetic field provides nullifying feedback to the SQIF that counterbalances a low-frequency portion of the external magnetic field, such that the output voltage of the SQIF detects a high-frequency portion of the external magnetic field. The circuit can be a receiver with the output voltage of the SQIF detecting an electromagnetic signal while the receiver is moving with changing orientation relative to the Earth's magnetic field.