An electromagnet assembly for supplying a region of concentrated
electromagnetic flux is provided. The assembly includes a flat strip of
an electrically conductive metal. The strip has a first and a second
opposite planar surfaces at least one of which is covered by a dielectric
material. The strip has first and second end portions. The strip is wound
in a coil including at least one first loop and one second loop and
disposing the second opposite planar surface in the first loop
substantially-adjacent the first opposite planar surface in the second
loop. The coil is disposed about an axis of symmetry configured to
concentrate electromagnetic flux at a midpoint on the axis of symmetry.
First and second electrical terminals are connected at the first and
second end portions, respectively.