Article identification and tracking using electronic shadows created by RFID tags

A tracking system uses RFID (radio frequency identification) tag technology to facilitate the identification and tracking of items in an environment through a technique known as shadowing. As an object or target moves within a pre-described detection zone with communicating antenna and RFID sensors, the object or target blocks the line of sight between respective antenna and sensors, preventing electromagnetic coupling between the sensor and the antenna and thus casting an electromagnetic shadow along the line of sight. One approach of this invention uses this shadow technique to perform functions such as theft (shrink) deterrence/detection; tracking the motion of objects through an environment by monitoring the shadow; and correlation analysis of people shadows to tagged items (e.g., merchandise, articles) to foster marketing and merchandizing effectiveness.