Patent ID: 6346884
Filing Date: 2002-02-12
Classification: G06K

Abstract:
An apparatus for identifying an article, comprising:at least one tag configured to be attached to the article and having an antenna coil and a RFID element connected to the antenna coil; and an interrogator configured to activate the tag by transmitting a radio wave with which the at least one tag resonates from a transmitting/receiving antenna, and configured to read and write data about the article to and from a memory of the RFID element, wherein the interrogator includes an oscillation circuit configured to sweep the radio wave transmitted from said transmitting/receiving antenna over a first predetermined frequency range including each resonant frequency of the at least one tag attached to a plurality of overlapped articles, and wherein the first predetermined range of frequencies includes a resonance frequency of each tag which varies based on a mutual inductance occurring between the antenna coils of overlapped tags.