Patent ID: 7198193
Filing Date: 2007-04-03
Classification: G06K

Abstract:
1. Apparatus for identifying a plurality of items each of which has a radio frequency transponder, which apparatus comprises: a conveyor for conveying the items; a three dimensional radio frequency antenna positioned on one side of the conveyor, the conveyor having a movable part for moving the items into and out of the antenna such that the items when in the conveyor are completely surrounded by the antenna; a reader for sending interrogation signals to the transponders via the antenna and for reading identification information from the transponders, wherein the three dimensional antenna comprises a plurality of coils mounted in a three dimensional arrangement to provide a three dimensional reading field in which all transponders in the reading field may be interrogated, means for interrogating the coils defining the reading field sequentially until all transponders are identified, and means for, after a transponder is identified, placing the transponder in a quiet mode to prevent that same transponder from responding to interrogation signals from the antenna.