RFID – Radio Frequency Identification – started in the 1970’s at the edge of technological capability. The idea of ID tags that could broadcast their identification seemed useful, particularly for expensive inventory that could justify the cost. The idea was also somewhat controversial, as it was easy to envision privacy issues with tags applied to many things – including people. Fast forward about twenty years: RFID is widely used, although not ubiquitous. Aiming to change the economics of RFID, a research group from Rice University (Texas, USA) and Sunchon National University (South Korea) has announced printed RFID tags composed of carbon nanotubes. The goal is to make RFID as easy to apply and as economical as barcode.
The ability to print the RFID ‘device’ into the packaging is a big advantage. It’s a three step process to print one-bit tags, which include antenna, electrodes, and dielectric layers on plastic foil (thin film media). These tags are passive; they don’t transmit information unless energized by radio waves at the correct frequency. Because they don’t need a power supply, their lifetime is almost unlimited.
Before this becomes commercial, the nano-RFID will need to be the size of standard bar codes and the range of transmission must increase. The research team is also working on increasing the tag’s digital capacity to 16 bits for more detailed information, and the ability to print the tags on paper
The technology reported in the March issue of the journal IEEE Transactions on Electron Devices is based on a carbon-nanotube-infused ink for ink-jet printers first developed in the Rice lab of James Tour, the T.T. and W.F. Chao Chair in Chemistry as well as a professor of mechanical engineering and materials science and of computer science. The ink is used to make thin-film transistors, a key element in radio-frequency identification (RFID) tags that can be printed on paper or plastic.
“Right now, the emitter has to be pretty close to the tags, but it’s getting farther all the time,” Tour said. “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.”