RFID DETECTION SYSTEM

摘要

A system (100) is disclosed for monitoring the position of one or more RFID tags (201). The system has a detector (301) incorporating circuitry (304) for detecting changes in the range of an RFID tag (201) from the detector and for triggering an alarm (401) if a detected change in range of an RFDI tag (201) exceeds a predetermined threshold or if the RFDI radio tag cannot be detected by the detector (301). Range may be detected, for example, by measuring the time of a returned radio signal from a tag (201), by measuring the strength of a returned radio signal from a tag, or by detecting changes in a periodic interval at which energy is transmitted by a tag.