Just How Small Is a Smaller RFID Tag?

swiftsureMay 26, 2016 –

North Carolina State University (NCSU) announced this month that its engineers had designed UHF RFID tags that are 25% smaller.

The question is, smaller than what? The answer takes some imagination and a look at a paper with a big title: Design of a Rectifier-Free UHF Gen-2 Compatible RFID Tag Using RF-Only Logic.

Cubic mm

This is a 1 mm cube. New RFID tag is .6mm x .3 mm.

It’s not uncommon to see press releases touting the newest “smallest” tag, and size has definitely shrunk over the last few years, making RFID a less cumbersome, more affordable asset management solution.

The NCSU tag, though, promises to take design a step further with technology that eliminates the hardware an RFID tag needs to convert alternating current (AC) to direct current (DC).

The new tag is .6 mm x .3 mm.

That’s smaller than a slice of a grain of sand. A sliver of half a honeybee brain. Tinier than a fruit fly egg.

New tags are tinier than a fruit fly egg

New RFID tags are smaller than a fruit fly egg

Perhaps easier to picture, it’s the size of a lower case “o” printed in Times New Roman 5.

Passive RFID tags use rectifiers to convert AC power to DC. NCSU’s innovation enables the tag’s logic to run directly from a radio signal, with circuits operating from AC power. The redesign makes a rectifier unnecessary.

“By eliminating the hardware that is used to convert the AC signal to DC for powering the circuit, we are able to make the RFID tag much smaller and less expensive,” said Paul Franzon, a professor of electrical and computer engineering at NCSU and the paper’s senior author.

The tags, with technology dubbed RF-only logic, have less range than a conventional EPC Class 1 Gen-2 passive RFID tag.

Reduced tag size often comes at the expense of read range. That works for some situations, such as near field communication (NFC) for access control and pay-by-phone. But tracking and managing assets in many environments – such as retail, data centers, manufacturing and supply chains – require read ranges of up to 20 feet.RF-only logic structure

The NCSU engineering team expects to develop RFID tags with similar range. If its technology evolves to allow minute tags with sufficient read range, it could dramatically improve high-speed automation processes and enable sensor applications with relatively small investments.

NCSU presented its paper on the miniaturized RFID tag May 5 at the IEEE RFID 2016 conference in Orlando, Florida.