4.Sensors

Different Sensor Designs

Some of the different Sensors being developed within the CRC 1261

In principle, different sensor types are suitable for measuring the relevant medical magnetic fields. Which design results in the highest resolution for each individual medical application, will be apparent later on in the development process. Therefore, five different sensor types are researched simultaneously in the CRC 1261.

Cantilever sensors consist of a thin silicon strip with, in the simplest case, two applied layers: One layer is magnetically active, the other one emits a voltage when its shape is changed. If the sensor is now brought into a magnetic field, the magnetic layer deforms and bends the silicon strip. Thereby, the second layer also deforms and emits a measurable voltage signal.

With the Surface Acoustic Wave sensor (SAW) the top layer of a crystal is caused to vibrate in such a way that a wave is created on its surface. A magnetic layer that can change its stiffness is applied on the surface of the crystal. If the sensor is then brought into a magnetic field the magnetic layer influences the propagation of the wave which again can be measured.