Lab steps up to challenges of RFID tech

Madison, Wis. — The UW RFID Lab at the University of Wisconsin-Madison aims to solve the host of thorny problems that prevent radio-frequency identification technology from becoming a truly cost-effective tool. For supply chain managers and RFID tag users, those issues range from the physics of signal propagation right up to logistics.

Alfonso Gutierrez, who heads the lab, acknowledged that "we have a ways to go" before achieving workable levels of cost and reliability for RFID technology. The lab, which last month opened its doors to the public for the first time, was founded as a collaborative, noncommercial "industry/university" forum to "analyze the true capabilities and limitations of RFID technologies — what works and what doesn't work," Gutierrez said.

In putting RFID tags into actual products, the devil is in the details. Gutierrez cited the potential technical challenges for a beverage company that wants to track canned soda with RFID tags. It's a challenge because the radio waves that underlie RFID technology can go haywire when placed close to certain items containing liquid or metal. For example, liquids, like soda in a can, tend to absorb the electromagnetic energy needed to power the RFID chip. Meanwhile, the metal of the soda can tends to reflect this energy, bouncing it around in unpredictable ways. In either case, the RFID signal sent by a chip to the reader faces interference, thus dramatically reducing read rates for RFID tags.

Nevertheless, the RFID industry has made significant strides in bringing new standards and new silicon to market. The Electronic Product Code Generation 2 (EPC Gen2) standard is in the ratification stage at the International Organization for Standardization. The standard will ensure that any RFID tags based on it can be read anywhere in the world. Many chip vendors, including Philips Semiconductors, Texas Instruments and Impinj, are sampling EPC Gen2-compliant RFID chips to reader makers and label manufacturers.

Even with new standards and agreements, when it comes to real-world implementation issues, such as "how product contents, packaging and media affect RFID performance," many questions remain largely unanswered, said Gutierrez.

An RFID tag consists of a microchip strapped into an inlay, antenna and substrate. The quality of the antenna inside each RFID tag matters, because it has a dramatic impact on RFID system performance and its overall network architecture.

The industry needs "millions of tags to bring down the cost of RFID," said Gutierrez. And yet, the physics of RFID technology doesn't allow a "one-size-fits-all approach," he noted. The industry may eventually need an antenna that's custom-designed just for soda in a can, or figure out an entirely new RFID-friendly packaging design for canned soda, Gutierrez predicted.