Anatomy of an RFID Tag: The VeriChip implantable RFID tag, shown below, is the only tag approved for use in humans for a medical application. It is a simple device consisting of a coil of wire and a hermetically sealed microchip within a glass capsule. The coil acts as an antenna and uses an RFID reader’s varying magnetic field to power the microchip and transmit a radio signal. Each VeriChip’s signal is a unique identifying number that links to a medical record database.