First and second spaced apart in-phase current loops at least partially
overlap in the axial direction. The first and second current loops may be
first and second arrays of in-phase current loops that are spaced apart
and at least partially overlap in the axial direction. First and second
arrays of arrays also may be provided that are spaced apart from one
another and that at least partially overlap in the axial direction.
Desirably high mid-field strength may be provided without violating
guidelines for far field radiation in the axial direction or in the plane
of the loops. A third array of in-phase current loops, an array of third
in-phase current loops and/or an array of arrays of third in-phase current
loops also may be provided that spaced apart from and at least partially
overlapping the second loops in the axial direction, opposite the first
loops. Third and fourth arrays of in-phase current loops also may be
provided that are spaced apart from one another, at least partially
overlap one another in the axial direction, and have different orientation
than the first and second current loops, to reduce and preferably minimize
nulls in the near field and mid field. A receive antenna also may be
provided between the overlapping portions of the first and second current
loops. By providing a receive antenna at this position, the effects of the
fields that are produced by the current loops on the receive antenna may
be reduced and preferably minimized.