Magnetic sensor with combined high pass flux concentrator and flux biasing circuit

A magnetic sensor for mobile applications comprising:

• a superconducting quantum interference device (SQUID);
• a superconducting, multilayer flux transformer having a pickup coil and an input coil, wherein the input coil is inductively coupled to the SQUID;
• a resistive element connected in series between the pickup coil and the input coil so as to function as a high pass filter such that direct current (DC) bias current below a threshold is impeded from flowing through the input coil;
• a flux bias circuit electrically connected in parallel to the superconducting flux transformer between the pickup coil and the input coil so as to provide a DC flux bias to the SQUID, wherein the resistive element and the flux bias circuit are configured such that a bias point of the magnetic sensor does not change as the magnetic sensor is rotated 0°, 90°, or 180° with respect to Earth's magnetic field, wherein the bias point has a voltage component and a B-field component, and wherein the flux bias circuit is a negative feedback loop for keeping a magnetic flux constant by scaling an input into the flux bias circuit by a factor of (1+ gain) -1;
• wherein the superconducting flux transformer is a 16 millimeter multilayer flux transformer;
• and
• wherein the magnetic sensor is mounted to a mobile platform.