Analytical Solution of Eddy Current Problem Due to a Figure-8-shaped Coil Above a Conducting Plate

The eddy current problems of a figure-8-shaped coil were studied with analytical method. The study was based on the theory of eddy current field due to a circular current loop in an arbitrary position above a conducting plate . Expression of impedance increment of the figure-8-shaped coil, as well as the eddy current distribution within conducting medium, versus the angle between the double loops of figure-8-shaped coil was presented. By the means of simulation, it was concluded that eddy current density in conducting plate excited by the figure-8-shaped coil was greater and its distribution was more concentrative compared with that by a current loop parallel to plate in the same conditions. The result could be applied in eddy current testing sensor design.