Smaller chips enable new RFID applications

Researchers at North Carolina State University (NC State) have made what is believed to be the smallest state-of-the-art RFID chip, which should drive down the cost of RFID tags. In addition, the chip’s design makes it possible to embed RFID tags into high-value chips such as computer chips, boosting supply chain security for high-end technologies.

“As far as we can tell, it’s the world’s smallest Gen2-compatible RFID chip,” said Professor Paul Franzon, corresponding author of a paper on the work. The paper was presented at the IEEE International Conference on RFID, held virtually from 27–29 April 2021.

Gen2 RFID chips are state of the art and are already in widespread use. One of the things that sets the new RFID chip apart is its size: it measures just 125 x 245 μm. Manufacturers have been able to make smaller RFID chips using earlier technologies, but Prof Franzon and his collaborators have not been able to identify smaller RFID chips that are compatible with the current Gen2 technology.

“The size of an RFID tag is largely determined by the size of its antenna, not the RFID chip,” Prof Franzon said. “But the chip is the expensive part.”

The smaller the chip, the more chips you can get from a single silicon wafer. The more chips you can get from the silicon wafer, the less expensive they are. “In practical terms,” said Prof Franzon, “this means that we can manufacture RFID tags for less than one cent each if we’re manufacturing them in volume.”

That makes it more feasible for manufacturers, distributors or retailers to use RFID tags to track lower-cost items. For example, the tags could be used to track all of the products in a grocery store without requiring employees to scan items individually.

“Another advantage is that the design of the circuits we used here is compatible with a wide range of semiconductor technologies, such as those used in conventional computer chips,” said Kirti Bhanushali, who worked on the project as a PhD student at NC State and is first author of the paper. “This makes it possible to incorporate RFID tags into computer chips, allowing users to track individual chips throughout their life cycle. This could help to reduce counterfeiting, and allow you to verify that a component is what it says it is.”

“We’ve demonstrated what is possible, and we know that these chips can be made using existing manufacturing technologies,” Prof Franzon concluded. “We’re now interested in working with industry partners to explore commercialising the chip in two ways: creating low-cost RFID at scale for use in sectors such as grocery stores, and embedding RFID tags into computer chips in order to secure high-value supply chains.”

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