摘要 |
An RFID system, which increases the probability of detection of an unused channel and which can reduce the effect of interference between reader/writers, has a reader/writer which has a reader/writer main unit and a polarization-switchable antenna and which transmits a continuous carrier wave, and a tag which modulates the continuous carrier wave with tag information and returns a response signal to the reader/writer; the reader/writer main unit judges the level of a received interference signal, determines a polarization direction for which the level of the interference signal is equal to or less than a threshold, transmits a command signal to the tag with a polarization direction different from the polarization direction thus determined, and receives a response signal from the tag to the command signal with the polarization direction thus determined.
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