According to independent research and analysis company IDTechEx, over 600 million RFID tags were delivered in 2005, and this figure could go up to 1.3 billion tags in 2006 and about 450 times that number in 2016. The company also expects the value of the total RFID market - including systems and services - to rocket to $26.23 billion, from $2.71 billion in 2006. EPCglobal has over 650 members, all coming from very diverse horizons but all dealing with complex supply chains or the enormous logistics of consumer goods. The organisation drives the technical requirements for the physical tags, and most importantly, defines the services and information-exchange schemes relative to the new data that can be derived from the use of EPC. The latter are detailed in the EPCglobal Architecture Framework to ensure a consistent and efficient flow of information between different trading partners. The EPCglobal network also offers numerous information services to its subscribers, including the Discovery Services that enable users to find data related to a specific EPC.
Tag specifications
For compliance with the EPC numbering and data-management schemes, various tag specifications have been issued by EPCglobal, the most prominent ones being for tags operating in the 13.56MHz ISM band (HF RFID with a typical reading range of 1m), and for tags operating in the 860 to 960MHz frequency range (UHF RFID with typical reading ranges of 5m, up to 10m). The EPC is currently defined as 96-bit long but the second-generation standard is extensible to 512-bit, to store data such as date and place of manufacture, lot number, or item serial number. The specifications of Class-1 Generation-2 UHF RFID tags open up a theoretical potential to read over 1,000 tags per second (in low-RF-noise conditions) but will also accomodate slower read rates in the range of 100 tags per second in noisy RF environments. The UHF gen 2 tag specification stretches to allow optional features such as unlimited user memory and will extend to several classes of tags to allow varying levels of complexity. Added user memory allows to read/write separate password-protected information about the tagged product (not covered in the EPC). Class 1 tags are designed to communicate their unique identifier and other information required to obtain this identifier during the communication process. They can be password-protected to 32-bit, and require a password to be killed (deactivated). Higher class tags could include active or semi-active (only active at certain checkpoints) devices with integrated sensor functionality (temperature sensors that log data on foodstuff along the supply chain). Although the UHF tags benefit from a longer read range, they do have some limitations when used on liquid-bearing packages or metallised items (UHF are more susceptible to absorption by liquids, and suffer antenna detuning with metals). But most "smart shelves" retail or distribution applications can already be addressed with the HF tag's reading range, with information relays through WiFi nodes for example. The imimmediate and most acclaimed benefits for end users (manufacturers and retailers) include - among other things - complete product traceability along the supply chain to avoid shrinkage, better monitoring of shelves and product displays with timely ordering and restocking, and detection of counterfeit (non-matching code) articles.
Current implementations
Philips' UCODE RFID chips, certified by EPCGlobal as Gen 2-compliant, add to the broad deployment of the EPC standard with different fully interoperable RFID labels and readers. The chips go to third-party RFID tag and label manufacturers. They feature a one-time programmable memory for the 96-bit EPC, cover all mandatory commands and provide a selection of optional commands as specified in the EPCglobal Class 1 Gen 2 standard. An anti-collision algorithm enables the reading of up to 1,600 labels per second under current US regulations, and up to 600 under current European regulations.Based on such chips, UPM Rafsec released its short dipole OneTenna Gen 2 inlay (Figure 1) for insertion into RFID labels or other substrates. The company can also provide these antennas readily integrated into self-adhesive RFID labels, supporting chips from silicon vendors such as Impinj, Infineon, EM Microelectronics, or ST Microelectronics.Coming from Alien Technology, the "Omni-Squiggle" tags ALL-9440 and ALL-9460 are two Gen 2 drop-in replacements for the company's previous-generation tags ALL-9338 and ALL-9340. They are optimised for most packaging applications, including the tagging of cases containing certain products with metal and liquid. The tags (Figure 2) are manufactured using a patented Fluidic Self Assembly process that allows very high volumes of EPC tags to be produced at low cost.Label manufacturer ASK designs disposable RFID paper labels, dubbed C.label. These consist of an RFID chip integrated into a paper packaging with a silver printed antenna. This RFID solution conforms to surfaces that bend and flex and can be affixed to pretty much anything, or laminated within customised pricing or branding labels (Figure 3). Whether they are designed to operate at high or ultra-high frequencies, most of these tags can be seamlessly integrated into labels or fabrics, doubling up as anti-theft devices. This is precisely what offers Checkpoint Systems, with a largege array of EPC-compliant tags for soft goods, to be embedded in paper but also in woven garment labels. For retailers, the added benefits over current implementations of electronic article-surveillance (EAS) systems, is the true read/write capability of each tag at various entry or exit checkpoints distributed throughout a shopping mall.
Moving towards printable RFID
For the huge volumes of tags that systematic item-level tagging would require, low production cost is a key factor. The revolution could come from printable electronics, whereby polymer-based RFID circuitry would be printed in high-speed, reel-to-reel in-line processes (instead of strapping a silicon chip onto an antenna inlay). A first step in that direction is to manufacture the label antennas using conductive inks rather than copper coils or foils. Texas Instrument, as well as producing a range of silicon RFID chips capable of over 1,000 write/erase cycles and a data retention of two years, delivers flexible Gen 2 antenna inlays (Figure 4) directly printed onto a 75-micron-thin PET substrate.XINK Laboratories flexographic printed RFID antennas rely on a proprietary silver ink that cures at ambient temperature. The process provides electrical performance equivalent to screenprint at up to 1/10th the ink consumption and 10 times the processing speed on regular commercial flexographic and gravure printing presses, claims the company. The materials are printable in a single pass and can be applied on a range of heat-sensitive substrates such as those used in pharmaceutical packaging, as well as most other regularly available PET and paper stocks.Pushing the logic further, polyIC is working on the development of complete polymer solutions and announced a functional HF RFID tag operating at 13.56MHz (Figures 5 and 6). The company is now focusing on adding memory bits to the plastic based chip and expect to ship very-low-cost non-EPC compliant RFID tags by the end of 2006. The RFID circuitry is directly printed on a standard polyester foil, using organic semiconductors and insulators to build up the necessary transistors. The manufacture of such tags on a roll-to-roll printing process would suit simple auto-ID and brand-protection applications.Also in the printed-electronics race, Philips Research just unveiled a stamp-sized 13.56MHz RFID tag. The paper-thinin prototype (Figure 7) is capable of transmitting multi-bit digital identification codes, and the company is confident that in the future it will be able to add enough memory bits to comply with standard EPC requirements. Scientists at Philips Research have also developed a 64-bit code generator, showing that plastic electronic circuits can be designed to the complexity required for item-level tagging. Reaching ultra high operating frequencies still remains a challenge for polymer-based electronics, and chemistry scaleability for volume manufacture is another issue to contend with, but printed electronics is already very promising for the HF RFID market.
Reading the bits
Regardless of the technology used for the tags, a plethora of RFID readers are available. These are the crucial link to the EPC network, since an EPC code in itself has little value. Typically, the readers are embedded into portals, gateways, floormats or any point of transition deemed appropriate for tracking the EPC tags. Portable readers are also part of the equation, such as ThingMagic's Mercury4h, a 25.4x25.4x3.8cm unit (Figure 8) that relies on advanced Software Defined Radio technology to be able to read any tag including ISO 18000-6B, EPC Class 0, EPC Class 1 and EPC Gen 2. The digital-signal-processing software can be upgraded to accept additional protocols. Among other features, the unit is 802.11x WLAN-enabled and boasts internet connectivity, so that it can feed the gathered data into networks, databases and business applications.
Derived data and privacy concerns
The overall benefits of RFID are obvious in terms of logistics, even more so since the EPC Network can pinpoint an item's location in the supply chain, remotely. Though, the use of these tags beyond the pure supply-chain management raises a lot of controversy, especially when some of these devices are embedded into consumer goods (not just the discarded packaging), such as clothes or footwear. Because both the tags and the readers can be easily concealed, item-level tagging opens up very tempting and possibly abusive post-purchase data-mining strategies. Looking at this aspect of the technology, consulting agency Stapleton-Gray & Associates founded the "Sorting Door Project" (www.sortingdoor.com). This research test bed on RFID, surveillance and privacy, explores the interrogation of tags "in the wild", using any number of collection points. It also looks at the exploitation of data according to collection context, tag and data associations over time, and what types of "educated guesses" can be derived from this. Clearly, the reach of the EPC goes far beyond the initial scope of RFID as barcode replacement in logistics. Some guidelines issued by EPCglobal include the use of a specific logo to indicate what products are EPC-RFID-enabled, and the option for consumers to "kill" the tag after purchase (deactivating the communication link). But for all practical purposes, these solutions may not be consistently implemented. This feeds strong debates among privacy advocates who fear that item-level tagging could mean constant tracking and monitoring of people's habits (maybe not just for marketing purposes). My conclusion on this, always read the small print.
