High magnetic field amplification for improving the sensitivity of Hall sensors

This paper describes the design of two magnetic concentrators that can be used to intensify the magnetic field in the active region of magnetic sensors, such as Hall sensors. The literature provides many examples of magnetic amplification, but magnetic gains never exceed 100 typically (Drljaca et al. 2001, Drljaca et al. 2002). We demonstrate that a larger magnetic field amplification (/spl sim/1000 and even higher) can be achieved. 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 an especially tailored magnetic concentrator; noise-equivalent magnetic induction spectral density (National Electronics Manufacturing Initiative spectral density) down to 10 pT//spl radic/(Hz) should be reached, using a good conditioning electronic.