US Patent 7812779 RFID transceiver sensitivity focusing system

Shielding of a particular material and geometry is interposed between a radio frequency identification (“RFID”) antenna transceiver and a zone to be monitored by the antenna. The shielding has an aperture therein that to some extent defines a degree of focusing of the radio frequency (“RF”) field associated with the antenna. RFID tags having appropriate RFID circuitry are only detected by the antenna when they pass within the focused RF field. The shielding is formed of a thin metalized plastic material, such as film used in forming anti-static material for storage of sensitive electronics. One particular formulation is primarily polyethylene film with an aluminum coating or layer thereon.