The Pacific Northwest National Laboratory (PNNL) in Richland, Wash., operating under the management of the U.S. Department of Energy, has been developing miniature RF tags for about 10 years. The culmination of this research is holding promise both for the U.S. military and civilian markets.
These tags store in-formation and use radio waves to communicate with a reading device similar to a bar-code scanner. The Department of De-fense, a major source of funding for the RF tag projects at PNNL, currently plans to use them to track both people and equipment in a wide variety of applications. Moreover, it is forecasted that these RF tags will enter the commercial sector as tracking devices for inventory, computers, cars, and even people.
The tags produced at PNNL are ideal for rapid, remote inventory tracking. While similar devices are available from other sources, the PNNL devices offer up to ten times longer ranges and simultaneous reading of up to 500 tags/s.
The tags can monitor external inputs like temperature and humidity and can control outputs like switches and valves. These features suit the devices for tamper detection or changing conditions and for remotely activating or disabling various kinds of equipment. Increased precision in tag-location detection has been demonstrated with a range and bearing of 0.1 m as well. Three categories of RF tags have been created at PNNL: passive tags, semi-passive tags, and active tags.
Passive RF tags are simple, low-cost solutions that require no battery and possess no moving parts (see the figure). These small devices suit short-range, simple tracking applications for high-value or high-security items. Information on 500 of these small, inexpensive tags can be read and updated in just one second. They offer a read/write range of 10 m. These models also possess the longest lifetime of the three versions.
Powered by a battery, semi-passive tags are designed for long-range monitoring applications. These devices have been proven capable of reading and writing from distances greater than 100 m. Line-of-sight access to tagged items isn't required. And, these tags can activate and deactivate items remotely. They can monitor external parameters such as temperature, pressure, shock, vibration, signs of tampering, and equipment activity.
Active tags are powerful battery-powered information transmitters capable of initiating communication. These devices can be read and updated from hundreds of kilometers away. They can monitor temperature, humidity, pressure, breakage, and other data that can help determine the physical condition of the items being tracked and monitored. Networks of active tags and predictive sensors can be constructed to collect and evaluate data in real time. Additional built-in decision-making abilities let these tags activate and deactivate tagged equipment based on information gained through input monitoring. Up to 50 tags can be read, updated, or engaged in active information transmission each second.
The U.S. military plans to utilize these devices to track people, machinery, and weapons. Experts forecast that the three models of RF tags will soon be used in various commercial applications, including supply-chain management, asset management, security, and consumer products.
For more information on the PNNL RF tags, go to www.pnl.gov/nsd.