All that hype surrounding radio-frequency identification (RFID), particularly those predictions for gargantuan growth in the retail supply chain, seems to have simmered down. Though it's bounced around for more than 20 years and has the support of industry consortium EPCglobal, Electronic Product Code (EPC) RFID tagging still waits to become the next big thing.
While implementation of the EPCglobal Gen 2 standard for supply-chain tagging has rolled out much more slowly than many analysts predicted, the program does continue to push forward. Before long, RFID carton and pallet tagging will join the dozens of other established RFID applications—from toll transponders to animal tags—that track and identify everyday items without line of sight and tie the physical world to the IT realm. Despite its snail-like progression, some heat remains behind the Gen 2 hype. The standard has united the tracking demands of major retailers like Target and Wal-Mart with the packaging initiatives of consumer-goods manufacturers. More importantly, EPC was the first major initiative to move RFID beyond its traditional closed-loop paradigm: Often, all parts of the system come from the same supplier, or at least they're precisely tuned for a given application. While such closed-loop systems work well, they aren't really relevant in the toolbox of electronic designers—except for those who have directly been designing the RFID systems. And now, that's starting to change.
With a combination of open standards and a potential ubiquity of low-cost readers and tagged goods, RFID is moving away from proprietary applications toward a more fluid future. Readers and tags will be embedded inside cell phones, laptops, and other electronic devices. As an electronic designer, you may soon find yourself designing RFID into your next product.
PAIRING UP
One key driver in this new wave of applications is the use of RFID for "pairing," or automatically identifying items that need to be coupled. These items can include electronics peripherals establishing communications or consumable components that need to be correctly matched or controlled.
EM Microelectronic, the semiconductor company of the Swatch Group, has implemented numerous projects where physical objects are logically bound via RFID. One example involves "smart refills" for electrical appliances with replaceable parts, such as electric toothbrush heads. Another is inkjet print cartridges that communicate their identity to a printer, which adapts its performance accordingly.
EM president Mougahed Darwish says that in pairing applications, an electronic device integrates an RFID reader chip, and the corresponding disposable or refill part integrates a transponder chip. The transponder operates as a configurable EEPROM, and the "host" device can then adapt its behavior according to the parameters that are communicated.
The miniaturization, low power, and new capabilities of the latest RFID reader ICs operating at 13.56 MHz make it easier for systems designers to develop embedded RFID applications, according to Johnsy Varghese, manager of high-frequency reader products at Texas Instruments.
The newest RF chips feature more functionality, such as an integrated analog front end, encoders/decoders, filters, voltage regulators, variable gain settings, automatic gain control (AGC), and available output supply and clock for external circuitry. These features reduce overall system complexity, bill of materials (BOM), and the need for additional software. Furthermore, smaller RF chip packages about the size of a quarter enable smaller system designs that expand the realm of products for embedded RFID.
Startup company SkyeTek focuses on low-cost embedded tag readers that can work with standards-based tags from any supplier. Having trademarked the term "tagnostic," SkyeTek CEO Rob Balgley says RFID readers have traditionally been designed for given markets, like the supply chain, and have been complex and expensive.
SkyeTek's goal is a common RFID architecture, creating a commonality around frequency protocol and choice of tags. "We make it a lot easier for somebody to make different design decisions. They don't have to get locked into a particular frequency or a particular protocol or even a particular tag, because we are pretty agonistic with regard to all three of those," Balgley says.
The company's HF and UHF products have the same mechanical, electrical, and software interfaces—even the same pin-outs. At the last minute, then, the designer can decide between UHF and HF. "Or, if you've got a whole family of products and you want to go in both directions, your inventory and stock is simplified," he says (Fig. 1).
SkyeTek's goal is the least expensive hardware platform with the greatest amount of functionality and performance in the software. When designing RFID for embedded systems, Balgley says, it's important to keep BOM cost low. "You don't want to hand somebody a BOM with a lot of expensive parts, high-end amplifiers, and parts like circulators, which, in and of themselves, can be $100 to $200," he says.
The M9 UHF SkyeModule uses low-cost cell-phone components. The UHF board costs $200, a price Balgley says is 50% lower than competitive modules, while offering a 3-m read range at 20 or 30 tags per second. SkyeTek also licenses its modules, driving costs lower and enhancing the level of integration.
The ease of embedding RFID technology is opening new markets, and SkyeTek foresees traditional RFID applications like inventory management and access control converging into one market. "There won't be this fragmented, nonconsolidated view of RFID. When there's one big market, that's where things get interesting in terms of being able to scale revenue and innovation," says Balgley.
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