Radio Frequency Identification (RFID) is a technology which uses radio waves to track, trace and identify a tagged entity. This process can be undertaken in various ways, a common one being initially storing identification data on an RFID tag which is attached to the entity. The tag consists of two components- a microchip which stores the data and an antenna which transmits the information to an RFID reader. The reader translates this information digitally for computers to analyze it further.
History of RFID:
RFID as a technology has been around for several decades, and has evolved into arguably the most potent tracking and identification technology in use today. The first crude use of this technology dates back to the World War II era when Germans instructed their pilots to maneuver their planes differently while entering their territory, so that the changed radar signal would confirm their identity. Prior to this, warring nations found it very difficult to know if a plane entering their territory was a friend or foe. Over the next twenty years, scientists from developed nations aggressively researched the subject before Mario Cardullo secured the first U.S. patent in 1973 for an active RFID tag.
During the 1970s, the U.S. government significantly increased RFID deployment, primarily in the transportation industry to identify vehicles entering a facility. The next 25 years saw gradual commercialization of RFID technology with a number of large companies entering the fray. Post 2000, the growth has been faster. RFID promises to revolutionize supply chain management by rendering obsolete existing bar code systems. Cost structure is a cog in the wheel of RFID systems, with end users reluctant to invest in expensive technology, particularly in current economic conditions.
RFID Frequencies:
RFID tags and readers have to be synchronized according to the required frequency. Some of the common frequencies are:
• Low Frequency ( LF) : 125 Kilohertz (KHz)
• High Frequency (HF) : 13.56 Megahertz(MHz)
• Ultra High Frequency (UHF) : 860-960 MHz
• Microwave : 2.45 Gigahertz(GHz)
The frequencies are chosen based on the requirements of the deployed applications. Each frequency has its intrinsic characteristics. LF tags utilize minimum power and are suited to tracking non metallic entities with high water content. This makes it ideal for tracking fruits and vegetables within a short range (about 1 foot). HF tags have a slightly greater range (about 3 feet) and are suited to tracking metallic objects. Where tracking over greater ranges is required, UHF and Microwave tags have to be used.
Active and Passive RFID tags:
RFID tags are classified as active or passive depending on whether they possess an internal power source or not. Active tags have batteries which power their circuits and transmit information to their readers. Active tags can read over long distances; broadcasting ultra high frequencies over a distance of 80 to 100 meters. They are expensive and hence their use is restricted to extremely valuable assets which need to be constantly monitored irrespective of distance.
Passive tags do not have any battery and rely on using power from their readers. These tags are inexpensive but cannot read beyond distances of about 6 meters. They are used for tagging items of lower value which are in close proximity with the reader.
Pricing:
There are two major factors which affects the cost structure of an RFID tag. Active tags are more costly than passive tags because of their power source and the additional hardware components. Another factor is the nature of data storage available. Storage can be read only, read-write and write once, read many. The price of a tag is directly proportional to the quality of data storage available.
Passive tags are quite inexpensive, and their price mostly ranges from 5 cents to 20 cents. Active tags are expensive, and their exact price is determined after taking into account the exact nature of range, frequency and deployment.
Applications:
Today, RFID is widely deployed in most industries. The retail industry uses RFID for efficient stock management, tracking paraphernalia and improving delivery timings. There is vast deployment of RFID in healthcare for patient and asset tracking. The manufacturing industry uses RFID to track WIP, improve production time and manage inventory. The pharmaceutical industry uses RFID for supply chain management, tracking legal/illegal drugs and stock management.
Within the automotive industry, most vehicles are now equipped with RFID chips for tracking in case of theft or accidents. These are just a few major industries which use RFID, but its potential assumes gargantuan proportions. With RFID being used from tracking cattle to ocean floor operations, there is little doubt that this will be one of the leading technologies of the new millennium.
Author: Santosh Antony
