US Patent 7511483 Device for sensing RF field

The device for sensing a RF field comprises a flux-receiving loop (1) including a circumferential path having a defined path width (d), the flux-receiving loop (1) having a portion (10) that transforms the magnetic flux flowing through the flux receiving loop (1) into a high magnetic field. The portion (10) comprises a constriction of the flux-receiving loop (1) that concentrates the current lines in the circumferential path to define a current-field transformer. At least one very low noise magnetic field transducer (12) is located at a very close distance from the constriction.