RFID 301. A detailed look at using RFID technology for tracking files. Tag Characteristics

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1 RFID 301 A detailed look at using RFID technology for tracking files For many offi ce managers, the key questions about RFID (radio frequency identifi cation) technology are about ease of use, cost effectiveness and productivity. Others, particularly those staff members who oversee information technology and systems integration, may want more detailon RFID performance and the differences among tags. Tag Characteristics Active tags An active RFID tag has its own power source (usually a battery). Because active tags can be read from up to 100 feet away, they are very useful for toll road collections and tracking hospital equipment, railcars, and other valuable assets. Because of their bulk and expense, active tags are not used on fi les or retail items. Passive tags Most tags (including those used in offi ces, libraries and retail establishments) are passive, meaning they contain no internal power source such as a battery. Instead, they are powered by signals generated by readers, which are also known as interrogators. Passive tags have several advantages over active tags. First, they are less expensive. Second, they are usually smaller and thinner. Finally, every battery eventually runs down; the absence of a battery signifi cantly extends the useful life of a passive tag. Passive tag frequencies Passive tags typically operate at a low, high or ultra-high frequency. This frequency determines a number of performance characteristics, including the distance at which the tag can be read by an interrogator. The typical readranges for commercially available tags are shown below: Frequency Low High Ultra-high 128 KHz MHz MHz Range 0-6 inches 0-36 inches 0-15 feet At present, most fi le-tracking systems use either high frequency (HF) or dual-mode ultra-high frequency (UHF) tags. The read-range of HF and UHF tags allows for effi cient and precise location by hand-held tracking devices. Global standards organizations have dedicated the MHz frequency to HF RFID, so those tags and interrogators are not likely to experience interference with medical and other devices. Tags operating at MHz are also less susceptible to be shielded by metal, furniture, walls or people. RFID 301 for File Tracking page 1

2 At this time, global standards organizations have not designated a clear worldwide frequency for UHF RFID. Interrogators and tags operate in a range of frequencies that vary by region: in Europe, the range is ; in North America, ; in China, and As a result, UHF systems could be more likely to suffer from interference problems caused by other equipment, such as badge readers, portable phones, and Wi-Fi systems. (For example, when the Chinese ranges were announced in 2007, industry reports speculated that signals in the RFID range could interfere with local aviation UHF applications. ) In addition, signals in the UHF range are inherently more susceptible to interference by metal and other materials. Durability versus cost RFID tags are typically designed for either supply chain management or asset-tracking applications and the distinction is important. With a supply chain tag (such as UHF tags for warehouses or HF tags found on retail merchandise), the emphasis is on low cost; durability is much less important because the item will be sold within a few months. Accelerated aging tests indicate that UHF tags typically begin degrading within two years of application. Degradation begins with a reduced read-range and proceeds to failure over a period of months. In an asset-tracking application (as in an offi ce, library or medical clinic), tag durability is critical. For offi ce fi le tags, materials and assembly processes are designed to ensure that the tag s longevity matches that of the item to which it is attached. (Some manufacturers will guarantee their tags accordingly.) In most cases, these tags are slightly more expensive than supply chain tags. Four Differences Among Tags Data capacity File-tracking tags typically have space for 256 bits of information, which is more than adequate for most current system demands. Some tags have room for up to 2,048 bits of information. Some offi ces and agencies want the extra space available in case data requirements change or a new, productivity-improving application is developed. Read/write characteristics With some RFID systems, information is permanently locked as soon as it is entered onto the tag. Other systems leave the data unlocked so that can be changed. An unlocked, rewritable system offers several advantages. First, if the original data entry is fl awed (due to operator error, for example) or if a fi le s unique identifi er is changed later, a rewritable tag can be easily revised. (A locked tag, in contrast, must be rendered inoperable or discarded and replaced with one containing the correct data.) A rewritable tag also allows for updates and revisions if emerging standards require changes in data content or formats. The durability of some HF rewritable tags also permits their reuse. Instead of adhering the tag directly to the fi le, some offi ces and agencies place it in an inexpensive tape pouch that is adhered to the fi le. If the fi le is no longer needed, the tag can be removed from the pouch when the fi le is discarded. The tag can then be reprogrammed for use on another fi le. These offi ces report four or more uses from a single tag; in theory, tags can be rewritten up to 100,000 times. RFID 301 for File Tracking page 2

3 Evolving Standards When a technology is fi rst being developed and commercialized, companies apply it in different ways. Over time, industries usually settle on common formats that will allow equipment from different manufacturers to interact. Thanks to these common formats, one manufacturer s computer (for example) can now operate software from hundreds of suppliers. RFID technology is evolving in a similar fashion. At fi rst, individual suppliers created proprietary models. More recently, individual nations have introduced country-specifi c standards for certain applications. In addition, a number of global RFID standards have been established and most observers expect this trend toward worldwide standardization to continue. The evolution of global standards could affect RFID tracking systems in two ways: If systems employ identical standards, global manufacturers would compete directly against each other, and that competition could drive down users costs for tags and interrogators. Once global standards are in place, future advancements in RFID technology will be based on those standards. A system that cannot migrate to those global standards will have limited ability to participate in the evolution of the technology. In both instances, offi ces and agencies will benefi t from working with a supplier that has a record of providing a migration path to updated standards and technologies. Furthermore, any migration path should allow blended tag handling. After new standards are adopted, most offi ces will go through a period during which some fi les have non-compliant legacy RFID tags and other fi les have new tags that refl ect the updated standards. Users will want assurance that that their RFID system will remain functional during this transition period, which could last for months or years. The evolution of RFID standards should not be a disincentive to investment. RFID systems provide immediate benefi ts in productivity and often pay for themselves in several years or less. In addition, manufacturers point out that RFID technology and the standards that govern it will continue to evolve for the foreseeable future. Offi ces and agencies should take advantage of the benefi ts that are currently available, but preserve the value of their investment by working with a supplier that provides a fl exible product that can be upgraded as new standards are published.. Quality Concerns The evolution of standards will ensure that RFID tags and readers have common characteristics, but it will not eliminate important quality and ease-of-use differences among systems. Tag quality is a particular concern. Tag malfunctions are not common but they can occur. (Imagine the stress on a poorly manufactured tag that is adhered to a thin fi le folder, where it is repeatedly fl exed and curled. Other stresses occur when a tag is subjected to high temperatures and humidity as it travels from the offi ce to a car or off-site location and then returned to the fi le room.) Unfortunately, poorly manufactured tags are not easily distinguished from more reliable, longer-lasting tags. When considering the purchase of an RFID system, an offi ce should ask the manufacturer about construction details (including the attachment of the antenna to the microchip, which can be a weak point), the adhesives, and the covering or sheathing, which protects the electronics from physical damage and environmental harm (from abrasion, for instance, or humidity). RFID 301 for File Tracking page 3

4 Leading manufacturers will also provide details on tag testing procedures. Testing should include initial qualification of materials (as well as subsequent supplier audits), but individual component quality is not enough. Each tag is, in fact, a lamination of multiple categories of materials adhesives, papers, films, chips and metallic antennas that can have negative interactions with each other. Over time, for example, some adhesives can introduce or accelerate corrosion in the bond between the chip and the antenna. Exposure to physical and environmental factors can also have deleterious effects on tags, producing corrosion, cracking or other damage. This can lead to total failure the tag goes dead or a severe reduction in the readrange. Similar problems can arise if fabricators do not understand and control the processes used to combine RFID components. Curing, lamination and the precise registration of RFID components are advanced processes that require sophisticated management and close monitoring to produce a reliable tag. Slight variations in curing time or assembly speed, for example, can have significant impacts on consistency and longevity. Because most offices expect their RFID tags to last as long as the items to which they are attached, they are especially concerned about the potential for failure after five or ten years. Accelerated aging tests, which usually involve exposure to high heat and humidity, are the most reliable technique for estimating durability over time. These tests which are used throughout the electronics industry last only weeks or months but can reveal flaws that would otherwise become evident only after a tag has been used for several years in the field. Established RFID manufacturers (those with more than a decade of experience) are now able to compare actual performance with initial projections of tag life using accelerated aging tests, and the results have confirmed the validity of these techniques. Detuning RFID tags are tuned to respond to a signal at a specific frequency. When an RFID tag comes in close proximity with metal (such as another tag), it can resonate at a slightly different frequency. This phenomenon is known as detuning. In rare instances, an item might not register because of detuning. Detuning can usually be eliminated if the employee fans the files when they are placed on a reader. Offices can also stagger the placement of RFID tags, making it less likely that tags on thin files will directly overlap on the reader. (Typically, the system software will provide confirmation that the file has been read.) Tags can also be shielded by metal, water and other materials. UHF tags are somewhat more prone to interference than HF tags. This difference is not pronounced in file rooms; the two types of tags will have similarly high reliability despite metal cabinets and shelves. In larger areas, however, the presence of walls, dividers, office equipment and metal furniture can compromise the theoretically longer read-range of UHF tags. RFID 301 for File Tracking page 4

5 Viruses and Vandalism Several academic papers have described a theoretical threat from RFID virus attacks. To avoid such an attack, well-designed systems use a carefully defi ned tag format that is validated for content and expected values. This protects it against malicious exploitation. In addition, a competent supplier will periodically review and update its software to eliminate any potential risks. RFID vandalism the destruction, defacement or removal of RFID tags is possible but highly unlikely, especially in an offi ce environment. RFID experts have also shown that it is possible to corrupt RFID tag data or to render the tags inoperable using a computer and a commercially available RFID reader-writer. As of this writing, no offi ce RFID systems (nor any public RFID installations such as libraries) have been attacked in this way. Health, Safety, Accessibility and Environmental Issues Like other employers, offi ces and agencies must be attentive to issues of accessibility, health and safety. In addition, they are responsible for the environmentally acceptable disposal of equipment and materials. In many countries, government agencies ensure compliance with accessibility, health, safety and environmental requirements. In other countries, independent certifi cation organizations perform this function. When compliance has been established, the products are often awarded a seal or mark of approval. The following example shows marks from several organizations and agencies, certifying compliance with requirements in the United States, Canada, China, the European Union and elsewhere. In the United States and some other countries, the premier certifi cation organization is Underwriters Laboratories (UL), which checks for compliance with product safety regulations. It also confi rms that equipment and materials meet the requirements of the Americans with Disabilities Act and workplace regulations outlined by the United States Occupational Safety and Health Administration (OSHA). OSHA regulations stipulate that equipment be certifi ed by UL or a similar organization. As always, failure to acquire proper certifi cation could have legal consequences for a manufacturer or purchaser if employees or clients are injured by equipment. Purchasers should also confi rm that the certifi cation applies to the assembled device, not just certain components. In addition, all radio frequency identifi cation devices are regulated by the Federal Communications Commission (FCC), an independent U.S. government agency. Purchasers of any radio frequency equipment should confi rm that it has been tested and certifi ed by the FCC. RFID 301 for File Tracking page 5

6 Other Performance Considerations RFID is not an emerging technology. It has been used in industrial and military applications for decades, and its performance and reliability are well documented. In addition, the broadening applications for RFID, especially in fi le-tracking and retail inventory control, have led to a gradual reduction in cost that is characteristic of an established technology. Nevertheless, RFID remains a fast-changing technology. In general, offi ces will have two concerns about the evolution of RFID: As the technology advances, will I be able to update my system? This depends on your supplier. Because improvements are inevitable, offi ces should work with suppliers that have a reasonable track record in the industry, a willingness to guarantee their equipment and tags, and a commitment to continued research and development. As standards change, will future systems be able to read my tags? This depends on your supplier and the direction that RFID technology takes. Purchasers should look for a system with fl exibility, so that it can evolve along with new standards as they are promulgated by international standards organizations. They should also work with suppliers who are committed to providing a migration path from the current generation of RFID technology to the next, and those that will follow. To see insights from our research and experience, including our list of white papers and case studies, visit d to learn more. 3M Track and Trace Solutions 3M Center Building 225-4N-14 St. Paul, MN USA Please recycle. Printed in U.S.A. 3M All rights reserved RFID 301 for File Tracking page 6