WIRELESS POWER SUPPLY-TYPE RADIO TAG SYSTEM

PROBLEM TO BE SOLVED: To provide an active-type wireless power supply-type radio tag system, in which a readable range is relatively freely settable, realizing a radio tag unnecessary of battery exchange similar to a passive type.SOLUTION: When a radio tag reader 1 instructs a wireless power supply unit 3 to start power supply, the wireless power supply unit 3 starts wireless power supply to a radio tag 2, and also superposes ID information and a command from the radio tag reader 1 with the power of the wireless power supply, to relay to the radio tag 2. The radio tag 2 is operated by the power supplied from the wireless power supply unit 3, and in response to the ID information from the radio tag reader 1, determines whether or not to report a self tag ID. On determining to report, the radio tag 2 transmits a radio signal including the self tag ID, to report it to the radio tag reader 1.