The shape of things to come

 Radio Frequency Identification (RFID) is becoming recognised as a technology of the future in defence operations. Adoption of the technology has not escalated as some commentators predicted a few years ago, but there is a steady increase in its use and as the cost of the technology reduces, uptake is steadily increasing.

Defining RFID
RFID systems are automatic identification systems that, using radio frequency signals, provide the automatic identification and location of electronic data-carrying devices attached to items.
    
Traditionally an RFID device that did not actively transmit signals to a reader was known as a tag. When signals were actively transmitted the device was known as a transponder. However, it has become common to interchange  both terms when referring to those devices, as will be done here.
    
RFID tags can be detected by radio frequencies at a remote distance from a reader without the necessity of contact, or to be in its line of sight because the radio frequencies between reader and tag can normally go through various materials. A network or computer management system can use the information retrieved by the readers for applications such as security management, materials management through a supply chain and other value-adding services.
 
Types of RFID tags
RFID tags should not be confused with Electronic Article Surveillance (EAS) Systems tags. RFID tags store information relating to the identification of an article. EAS tags are commonly attached to items to protect them from theft. The tag is attached to merchandise and when a sale occurs the tag is removed or de-activated. If an activated EAS tag passes into the sensors’ magnetic field it disrupts this field and results in an alarm.
    
RFID tags comprise a semi-conductor chip with memory processing capability and a transmitter connected to an antenna. The memory may be configured to be read only (RO), write once, read many times (WORM), or read/write (RW). Additionally, recent developments have led to the creation of RFID tags that do not require a chip – “chipless tags”. However, these tags are more limited regarding their performance in data storage, range and data transfer when compared with chip-based tags, but their low cost may justify the use on some applications that do not require those performance levels e.g. anti-counterfeiting applications. Therefore RFID tags can be divided in chip-based tags and chipless tags.  
    
RFID tags take on many forms. If they take the shape of a card (e.g. credit card type) containing a microchip they are referred as “contactless chip cards” and are mainly used for payments, identification, information collecting or combination of the above. In contactless chip cards, the power supply and the data exchange between reader and transponder are achieved by the use of magnetic or electromagnetic fields. In this case, contact surfaces provide energy to the card for the occurrence of data transfer. This type of tag is refered to as a “passive tag”.
    
Sometimes it is necessary to use batteries in tags when there is the need to achieve increased distances between reader and transponder but this increases the tags’ price. When tags use support batteries they are referred to as “active tags”. Active tags have a battery for two reasons: for keeping the tag circuitry running and for communication with the tag reader. The power supply impacts on cost and, to some extent, robustness of the tagging technology.
    
When the card contains a processor chip that provides computing capacity it is called a “smart card”. These cards are mainly used in secure sensitive applications like financial transactions, transport tickets or smart cards for mobile communications.

Uses of RFID
RFID systems should not be seen as a substitute for other identification systems like barcodes. Their multifunctional capability can provide additional features that allow the use of this technology for other applications that consequently add value and increase security. RFID can be used to address the following important issues within a variety of sectors.

Conclusion
RFID tags with there ability to store, transmit and receive data offer significant opportunities for the defence sector. They are well placed to increase the robustness and security of operations. Within the defence sector RFID is already being exploited in a variety of areas including asset and product tracking, theft detection and access control. It has been argued that the only thing limiting the application of RFID is the imagination of the end users.
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