Active RFID tags, on the other hand, have an internal power source, and may have longer range and larger memories than passive tags, as well as the ability to store additional information sent by the transceiver. At present, the smallest active tags are about the size of a coin. Many active tags have practical ranges of tens of metres, and a battery life of up to 10 years.
Because passive tags are cheaper to manufacture and have no battery, the majority of RFID tags in existence are of the passive variety. As of 2004, these tags cost from US 0.40 at high volumes. Universal RFID tagging of individual products will become commercially viable at very large volumes of 10 billion units per year, driving production cost to less than US 0.05 according to one manufacturer.
The RFID system
An RFID system may consist of several components: tags, tag readers, edge servers, middleware, and application software.
The purpose of an RFID system is to enable data to be transmitted by a mobile device, called a tag, which is read by an RFID reader and processed according to the needs of a particular application. The data transmitted by the tag may provide identification or location information, or specifics about the product tagged, such as price, color, date of purchase, etc. The use of RFID in tracking and access applications first appeared during the 1980s. RFID quickly gained attention because of its ability to track moving objects. As the technology is refined, more pervasive and possibly invasive uses for RFID tags are in the works.
In a typical RFID system, individual objects are equipped with a small, inexpensive tag. The tag contains a transponder with a digital memory chip that is given a unique electronic product code. The interrogator, an antenna packaged with a transceiver and decoder, emits a signal activating the RFID tag so it can read and write data to it. When an RFID tag passes through the electromagnetic zone, it detects the reader's activation signal. The reader decodes the data encoded in the tag's integrated circuit (silicon chip) and the data is passed to the host computer for processing.
Take the example of books in a library. Security gates can detect whether or not a book has been properly checked out of the library. When users return items, the security bit is re-set and the item record in the Integrated Library System is automatically updated. In some RFID solutions a return receipt can be generated. At this point, materials can be roughly sorted into bins by the return equipment. Inventory wands provide a finer detail of sorting. This tool can be used to put books into shelf-ready order.
Current usage
- Low-frequency RFID tags are commonly used for animal identification. Pets can be implanted with small chips so that they may be returned to their owners if lost. Beer kegs are also tracked with LF RFID. Two RFID frequencies are used in the United States: 125 kHz (the original standard) and 134.2 kHz (the international standard).
- High-frequency RFID tags are used in library book or bookstore tracking, pallet tracking, building access control, airline baggage tracking, and apparel item tracking. High-frequency tags are widely used in identification badges, replacing earlier magnetic stripe cards. These badges need only be held within a certain distance of the reader to authenticate the holder. The American Express Blue credit card now includes a high-frequency RFID tag, a feature American Express calls ExpressPay.
- UHF RFID tags are commonly used commercially in pallet and container tracking, and truck and trailer tracking in shipping yards.
- Microwave RFID tags are used in long range access control for vehicles.
- Some smart cards embedded with RFID chips are used as electronic cash, e.g. Octopus Card in Hong Kong and the Netherlands and United Kingdom (In the form of the London Underground Oyster Card) to pay fares in mass transit systems and/or retails.
Passports
A number of countries have proposed to implant RFID devices in new passports, to facilitate efficient machine reading of biometric data. Security expert Bruce Schneier said of these proposals: "It's a clear threat to both privacy and personal safety. Quite simply, it's a bad idea." The RFID-enabled passport uniquely identifies its holder, and in the proposal currently under consideration, will also include a variety of other personal information. This could greatly simplify some of the abuses of RFID technology, and expand them to include abuses based on machine reading of data such as a person's nationality. For example, a mugger operating near an airport could target victims who have arrived from wealthy countries, or a terrorist could design a bomb which functioned when approached by persons from a particular country.
The US State Department initially rejected these concerns on the grounds that they believed the chips could only be read from a distance of 10 cm (4 in), but in the face of 2,400 critical comments from security professionals, and a clear demonstration that special equipment can read the test passports from 30 feet (10 m) away, as of May 2005 the proposal is being reviewed.
Recent Comments