| 摘要 |
An extended-range reader for use in identifying the tag of an object. The reader includes a winding of conducting wire for generating an interrogating magnetic field. The winding may be either a coil assembly consisting of a plurality of coils spaced at intervals along a common axis or a solenoid. The winding is limited to those having values of D/L less than four where D is the smallest transverse dimension of the winding and L is the length. The winding is adapted to receive a structure within the winding for providing objects a passageway through the winding. The axis of the winding may be either straight or curved. To improve the magnetic field generating capability of the winding, a magnetic shunt encircling the winding can be added. Also included is a structure within the winding for providing objects a passageway through the winding, the structure having openings for object ingress and egress. Where the structure is intended to provide a natural environment for the objects, the structure, except for the openings, can be made pervious or impervious to liquids or gases.
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