Radio-frequency identification (RFID) is the wireless non-contact use of radiofrequency electromagnetic fields to transfer data, for the purposes of automatically identifying and tracking tags attached to objects. RFID tags contain electronically stored information, some of these tags are powered by and read at short distances by magnetic fields. Others are powered by battery, or collect energy from the interrogating EM field, and then act as a passive transponder to emit microwaves or UHF radio waves. Battery powered tags are able to operate from hundreds of meters away. Unlike a barcodes, the RFID tag doesn’t need to be within the line of sight of a reader, which allows them to be embedded in the object to be tracked.
RFID tags can be used in many different industries. A tag can be attached to an automobile during it’s production, it can then track the vehicle’s progress through the assembly line. Pharmaceuticals can be tracked during shipment. Livestock and pets can have RFID tags injected into them, allowing positive identification of the animal and it’s location. RFID tags are used on offshore oil and gas platforms to track personnel as a safety measure. When worn in clothing the personnel can be located 24 hours a day and be quickly found in emergencies.
The first RFID Tag
The modern RFID tag can be traced back to 1973, when Mario Caudullo patented a passive radio transponder with memory. The initial device was powered by an interrogating signal and was demonstrated for use in automatic vehicle identification for unmanned toll systems, electronic license plates, electronic manifests, vehicle routing and vehicle performance monitoring. Other proposed uses were in the field of banking, to be used for electronic checkbooks and credit cards. Also for use in security, including personal identification, automatic gates and surveillance, among other uses.
An RFID system uses tags or labels attached to an object. Two-way radio transmitter-receivers called interrogators or readers send a signal to the tag and read it’s response. RFID tags can either be passive, active or battery assisted passive. An active tag has a battery, and occasionally transmits its ID signal. A battery assisted passive (BAP) has a small battery located in the device and is activated when scanned by a RFID reader. A passive tag is less expensive and smaller since there isn’t a battery in the tag.
RFID tags can either be read-only, which have a factory-assigned serial number that is used as a key into the database, or they can be read/write, where object-specific data can be written into the tag by the system user. Field programmable tags may be write-once, read-multiple. Blank tags can be written with an electronic product code by the user.
A Passive Reader Active Tag (PRAT) system has a passive reader which only receives radio signals from battery operated, transmit only tags. An Active Reader Passive Tag (ARPT) system uses active tags that have been activated by an interrogator signal from the active reader. A variation of this system can also use a Battery Assisted Passive (BAP) tag which acts like a passive tag but has a small battery to power the tag’s return reporting signal. Fixed readers are used to create a specific interrogation zone which can be controlled. This makes it possible for a targeted reading when the tags travel through the interrogation zone. Mobile readers can easily be handheld or mounted on a traveling cart.
Uses in Asset Management
When RFID tags are combined with mobile computing and Web technologies they provide a means for companies to identify and manage their assets. Mobile computers, with integrated RFID readers, now have the capabilities to deliver a complete set of tools that eliminate the need for extensive paperwork, while giving proof of identification and attendance. This system also eliminates the need for manual data entry.
An automatic identification control system that is based on RFID technology has a significant value to inventory control. The system can provide accurate information of a company’s current inventory. An example of this was proved in a study that was held by Wal-Mart. The use of RFID technology reduced Out-of-Stock instances by 30 percent for products that sold between 0.1 and 15 units a day. RFID tags can also help a company ensure the security of their inventory. With the use of just in time tracking of inventory using RFID, the computer data can show whether the inventory stored in the warehouse is correct with current readings. Other major benefits to using RFID include the reduction of labor costs, the simplification of business processes and the reduction of inventory mistakes.
The tracking of products, using RFID, can begin with the production of the item, then proceed through the whole process of shipping and receipt by the customer. In 2005, the Wynn Casino in Las Vegas, began placing individual RFID tags on their high value chips. These tags allowed the casinos to detect counterfeit chips, track betting habits of individual players, speed up chip tallies and determine counting mistakes made by dealers. In 2010, the Bellagio casino was robbed of $1.5 million in chips. The RFID tags in these chips were immediately invalidated, which made the cash value of the chips nothing.
RFID uses in Transportation and Logistics
Logistics and transportation are areas that greatly benefit from the use of RFID technology. Yard management, shipping and distribution centers use RFID tracking technology extensively. In the railroad industry, RFID tags mounted on locomotives and rolling stock identify the owner, identification number and type of equipment including its characteristics.
EPCglobal has worked on international standards for the use of mostly passive RFID and the Electronic Product Code (EPC) in the identification of many items in the supply chain for companies worldwide.
One of the missions was to simplify the Babel of protocols prevalent in the RFID world in the 1990s. In 2004, the Hardware Action Group created a new protocol, the Class 1 Generation 2 interface, which addressed a number of problems that had been experienced with Class 0 and Class 1 tags. The EPC Gen2 standard was approved in December 2004. This was approved after a contention from Intermec that that standard may infringe a number of their RFID-related patents. It was decided that the standard itself does not infringe their patents, making the standard royalty free. The EPC Gen2 standard was adopted with minor modifications as ISO 18000-6C in 2006.
We have only scratched the surface on discovering the possibilities that RFID provides for companies of all sizes as well as many aspects of life in general. The possibilities are seemingly endless and the benefits are incomparable.