RFID Electronic Identification Technology: Animals

Animal RFID tags are based on passive tag technology. ...

RFID Electronic Identification Technology: Animals: Via USDA: Animal Electronic Identification

... "All transponders contain a microchip and an antenna. Transponders can be classified as active or passive depending on whether their power source is internal or external. Passive transponders are used in livestock because they get their power from the reader device (antenna). The power antenna transmits radio frequency bursts and the passive transponder returns a coded signal to a separate antenna. A transmission link, via radio waves, is established between the transponder and the reader device (antenna). Animal electronic identification technology uses passive Radio Frequency Identification (RFID) because it is cost effective and offers the characteristics desired for animal identification. RFID technology does not suffer from signal absorption by tissue or moisture, and it can be packaged differently without affecting performance. " ...