19 March 2010

Checkout's days numbered as printable RFID tags become a reality

by Kate Melville

Using nanotube transistors, Rice University researchers, in collaboration with a team led by Gyou-jin Cho at Sunchon National University in Korea, have come up with an inexpensive, printable transmitter that can be invisibly embedded in product packaging. The tag will allow a customer to walk a cart full of groceries or other goods past a scanner which would read all items in the cart at once, total them up and charge the customer's account.

The technology, reported in IEEE Transactions on Electron Devices, is based on a carbon-nanotube-infused ink that can create thin-film transistors, a key element in radio-frequency identification (RFID) tags.

"We are going to a society where RFID is a key player," said Cho, a professor of printed electronics engineering at Sunchon, who expects the technology to mature in five years. Cho and his team are developing the electronics as well as the roll-to-roll printing process that, he said, will bring the cost of printing the tags down to a penny apiece and make them ubiquitous.

RFID tags are almost everywhere already. The tiny electronic transmitters are used to identify and track products, shipping containers and farm animals. But RFID tags to date have been largely silicon-based. Paper or plastic tags printed as part of a package would cut costs dramatically.

Printable RFIDs are practical because they're passive. The tags power up when hit by radio waves at the right frequency and return the information they contain. "If there's no power source, there's no lifetime limit. When they receive the RF signal, they emit," said Rice's James Tour.

But there are several hurdles to commercialization. First, the device must be reduced to the size of a bar code, about a third the size of the one reported in the paper, Tour explained. Second, its range must increase. "Right now, the emitter has to be pretty close to the tags, but it's getting farther all the time. The practical distance to have it ring up all the items in your shopping cart is a meter. But the ultimate would be to signal and get immediate response back from every item in your store - what's on the shelves, their dates, everything."

"At 300 meters, you're set - you have real-time information on every item in a warehouse. If something falls behind a shelf, you know about it. If a product is about to expire, you know to move it to the front - or to the bargain bin," he added.

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Source: Rice University