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This paper presents the study of a novel bar-shaped magnetic shielding for magnetoresistive (MR) sensors in current measurement on printed circuit boards (PCB). The main physical principles of the shielding effect were studied by using the analytical model of magnetic flux concentration. Finite element analysis (FEA) simulations were used to simulate the shielding effects with changing geometrical parameters of the bar-shaped magnetic shielding. The dependences of the shielding effect on the parameters of length, width and thickness were analyzed. It shows that these parameters are critical for designing magnetic shielding. This new concept of magnetic shielding for MR sensors in current measurement on PCB was experimentally tested and verified in a laboratory setup. The experimental results verify the feasibility and effect of this novel magnetic shielding for MR sensors. [ABSTRACT FROM PUBLISHER]

Abstract: This paper presents the study of magnetic flux concentration phenomenon of magnetic flux concentrators (MFCs) at the micrometer scale. The main physical principles of magnetic flux concentration were studied by using analytical calculations and finite element method (FEM) simulations. The dependences of achievable maximum magnetic gain on the three critical parameters were analyzed. It shows that material, aspect ratio, and shape are three critical parameters for designing MFCs. Three typical MFCs were designed for magnetoresistive (MR) sensors in applications. The magnetic gain and linear working range of the MFCs were studied and compared. By using the same high-permeability magnetic material (nickel–iron alloy, μ r ≈104−105), the MFCs of different geometries perform differently in magnetic amplification. The T-shaped concentrator shows higher magnetic amplification with magnetic gain G= 56 but comparatively narrower linear working range of 1.6mTesla. The bar-shaped concentrator occupies smaller space and provides 62.5% wider linear working range (2.6mTesla) than the T-shaped concentrator but at the expense of 32.1% smaller magnetic gain (G= 38). In the respect of magnetic gain, the triangle-shaped concentrator (G =51) is comparable with the T-shaped concentrator. It provides a 42.3% wider linear working range (3.7mTesla) than the bar-shaped concentrator. [Copyright &y& Elsevier]