Finite element simulation to improve the sensitivity of a MIT

In the field of magnetic inductance tomography, signal processing is a real challenge. This is due to the divergent nature of magnetic fields. The sensitivity, i.e. the change in the receiving signal by means of an electrically conductive sample in a measuring volume depends strongly on the positioning of the sample. Objects that are located near the transmitting or receiving coils are very well locatable, where objects in larger distance are hard to detect. In this paper an approach is presented that improves the topology of the magnetic fields in the “magnetic induction tomography” (MIT) by changing geometric constructions and current patterns of coils so far, as to allow a sharper localization of objects within the space. The aim is to level the distribution of the sensitivity in the measuring volume, so that electrically conductive objects with a larger distance between transmitting and receiving unit can be detected with almost the same signal intensity as objects close to the transmitting and receiving unit. The simulation tool Comsol© is used for the geometric modeling making a finite element analysis (FEA). The subsequent signal processing and analysis of the simulation results are implemented in Matlab©. Within this FEA the coil geometries and current patterns are changed numerically, so that the minimum object size, that is still detectable, is, compared to the known MIT, reduced and the sensitivity of the system is improved. To validate the simulation in Comsol©, first simulation results are compared with analytical models and analyses.