Researchers at North Dakota State University have developed an RFID tag that neatly solves the problem of metallic interference — it uses the metal it's attached to as an antenna. Traditional RFID tags contain both an integrated circuit and antenna for broadcasting information. While this works well for most materials, metal surfaces tend to interfere with small antennas and cause them to be unreliable. Current solutions to this problem include adding a buffer between the tag and the metal object it's tracking, but this often results in bulky tags that stick off the object as much as three centimetres and are easily damaged during shipment.
A team at the university's Center for Nanoscale Science and Engineering came up with a solution that's a bit more elegant: a tag that gets rid of the antenna and uses the whole metal object for transmitting signals. By using highly-permeable materials for the tag, current is absorbed by the metal container and sent to the integrated circuit. This results in tags less than three millimetres thick and allows them to be recessed into objects, such as canned goods or oil drums. While there are numerous industrial applications for the new tags, we'll have to see if the technique can be applied to consumer products — the university is looking for partners and licensees now.