Communications system for an RFID tag having an inductive antenna device detachable or movable

An RFID (Radio Frequency IDentification) tag communications system comprising:

• an RFID tag including an RFID chip and a tag antenna connected to said RFID chip;
• an RFID access device for activating wireless communication for accessing said RFID tag;
• and
• an inductive antenna device including an access-device-side antenna capable of being electromagnetically coupled with an antenna of said RFID access device, a tag-side antenna capable of being electromagnetically coupled with said tag antenna, and a conductive line for electrically connecting said access-device-side antenna and said tag-side antenna,
• said RFID tag comprising:
• an electromagnetic shield for forming a space including said RFID chip and said tag antenna into an electromagnetically shielded space;
• and
• a positional-relationship controller for providing a first positional relationship and a second positional relationship as a relative positional relationship between said inductive antenna device and said RFID tag,
• said first positional relationship making possible electromagnetic coupling between said tag antenna and said tag-side antenna staying in said electromagnetically shielded space with said access-device-side antenna positioning outside said electromagnetically shielded space,
• said second positional relationship making impossible electromagnetic coupling between said tag antenna and said tag-side antenna.

An inductive antenna device intervening in communication between an RFID (Radio Frequency IDentification) tag including an RFID-chip and a tag antenna connected to the RFID chip and an RFID access device for activating wireless communication for accessing the RFID tag, comprising:

• an access-device-side antenna capable of being electromagnetically coupled with an antenna of the RFID access device;
• a tag-side antenna capable of being electromagnetically coupled with the tag antenna;
• and
• a conductive line for electrically connecting said access-device-side antenna and said tag-side antenna,
• a first positional relationship and a second positional relationship being provided as a relative positional relationship of said inductive antenna device to said RFID tag,
• said first positional relationship making possible electromagnetic coupling between the tag antenna and said tag-side antenna staying in an electromagnetically shielded space provided in the RFID tag with said access-device-side antenna positioning outside the electromagnetically shielded space,
• said second positional relationship making impossible electromagnetic coupling between the tag antenna and said tag-side antenna.