Air Coil a security badge and a transponder

摘要

In one aspect, the present invention provides an air coil 20. The air coil 20 may be made from a strip of electrically conductive material 22 which has an insulating material overlying it. For example, the conductive material may comprise copper. The strip 22 is wound into a coil to perform a plurality of windings. The insulating material electrically insulates each of the windings from adjacent ones of the windings.