Magnetic field sensor comprising a sensor circuit board

A magnetic field sensor, comprising:

• a microwave source;
• and
• a sensor circuit board, wherein the sensor circuit board includes:
• a sensor crystal with at least one magneto-optical defect, wherein the sensor crystal is disposed such that microwave radiation generated by the microwave source can be absorbed by the at least one magneto-optical defect of the sensor crystal,
• an excitation light source configured to emit an excitation light beam and is configured and disposed such that the excitation light beam emitted by the excitation light source can cause an emission of fluorescence radiation in the at least one magneto-optical defect of the sensor crystal,
• a detector which is configured and disposed such that the detector detects the emitted fluorescence radiation, and
• and at least two permanent magnets which are disposed and configured such that the at least two permanent magnets generate a homogeneous static magnetic field in the sensor crystal.

A method for producing a magnetic field sensor, comprising the following steps:

• producing a sensor circuit board;
• fitting the sensor circuit board with an excitation light source, at least one detector, and a sensor crystal such that an excitation light beam generated by the excitation light source can cause an emission of fluorescence radiation in the sensor crystal and the detector can detect the fluorescence radiation;
• and
• fitting an inner layer and/or an underside and/or an upper side surface of the sensor circuit board with at least two permanent magnets in such a way that a homogeneous static magnetic field can be generated in the sensor crystal, wherein a first or a first group of the permanent magnets are first disposed on and fastened to the inner layer and/or an underside and/or an upper side of the sensor circuit board, then a second or a second group of the permanent magnets are disposed on and fastened to the inner layer and/or the underside and/or the upper side of the sensor circuit board, and when the inner layer of the sensor circuit board has been fitted with permanent magnets, connecting the inner layer fitted with permanent magnets to the upper and the underside of the sensor circuit board, by lamination.