Design of planar magnetic concentrators for high sensitivity Hall devices

We have studied the sensitivity of Hall devices using planar magnetic flux concentrators of different shapes in high permeability amorphous alloys. Modifying the shape of magnetic concentrators, amplification and linear working range are optimized. In this paper, we present numerical results to optimize the amplification of the external field for different concentrators shapes. A physical approach to understand the impact of the shape on the amplification is proposed. Experimental data (using a combination of micro-integrated and macroscopic magnetic flux concentrators) underline the theoretical predictions. We show that choosing the appropriate magnetic concentrator design, one can gain 50% of amplification for the same linear working range by using the tanga concentrators instead of simple bar-shaped ones. We obtained 30.2 V/T absolute sensitivity, using tanga-shaped concentrators with a length of 10 mm. This is 300 times better than the sensitivity of conventional Hall device. (C) 2002 Elsevier Science B.V All rights reserved.