This paper describes the design of a set of two magnetic concentrators which can be used to intensify the magnetic field in the active region of magnetic sensors, such as Hall sensors. Literature provides many examples of magnetic amplification, but magnetic gains never exceed 100 typically [1, 2]. We demonstrate that larger magnetic field amplification (∼1000 and even higher) can be achieved by implementing an appropriate geometry. Magnetic field amplification can even exceed the theoretical value fixed by the relative permeability of the material. Thus the effective sensitivity of Hall sensors can be improved by at least three orders of magnitude by implementing them inside especially tailored magnetic concentrators; noise-equivalent magnetic induction spectral density (NEMI spectral density) down to 10 pT/√Hz should be reached, using a good conditioning electronics. We present a formulation of our design process as an optimization problem and use it to find an optimum shape for the magnetic concentrators in a simple case.
Print ISSN: 0171-8096
Volume: 73, 06/2006
Pages: 339 - 349