Planar magnetic harmonic sensor for detecting small quantities of magnetic substances

摘要

A device is disclosed for detecting the presence and/or determining the configuration of a magnetic substance. The device includes a magnetic circuit having a magnetic core and an air gap. Coupled to the magnetic circuit are an excitation coil, for periodically driving the magnetic circuit into saturation, and a measurement coil, for measuring the effective appearing permeability of the magnetic circuit in the presence of the magnetic substance.