Method Of And Apparatus For Long Distance Reading Of Passive Tags In Radio Frequency Identification Systems

摘要

In accordance with the present invention, it is attached to the object 12 to be identified and tracked by the radio frequency identification system reading method and apparatus of the passive tag (11) is disclosed. Inquiry transmits a predetermined radio frequency interrogation signal towards the passive tag 11 via the antenna array 10 receives the response signal from the tag 11 through the same array 10. This response signal to the electronic circuit for processing (20 to 25) is provided with a phase conjugator to the phase to be conjugated to each of the received signal 23, the phase-conjugated signals are transmitted back to the passive tags (11). Reverse orientation of the antenna array obtained through the phase conjugate enables accurate object identification and tracking also in the relatively far distance.