What Is RFID?by John Landers
Radio frequency identification (RFID) refers to a transmitting device, or tag, that is smaller than a dime. It can be embedded in a product, an animal or a person's skin. RFID tags communicate information to a reading device.
RFID works by allowing an integrated circuit to gather and process data. An RFID tag has an antenna, which receives and transmits signals.
Three types of RFID tags are available: active, passive and battery-assisted passive (BAP). Passive RFID doesn't have a battery or external power source.
RFID tags are used in passports, transportation passes, inventory tracking, animal identification and information technology. The United States has required RFID technology in passports since 2006; the tag stores the same information that is on your passport and a digital photo.
Large numbers of RFID tags can be read instantaneously. The tags can be disposable or durable.
In her 2006 book "Spychips," RFID opponent Katherine Albrecht expresses concern over IBM's quest for a patent on a type of RFID technology that she says could lead to the tracking of people. IBM says the technology would keep track of customers' shopping habits inside stores.