RFID: The Chips Are Down

April 1, 2002
"Chipless" RFID tags are examined in a new report. Are they as promising as they seem?
RFID: The Chips Are Down

This isn’t another “RFID has finally arrived!” column for two reasons. First, RFID (radio frequency identification) has already arrived and has been performing admirably in many applications around the world for a number of years. Second, because RFID is continuing to evolve, we’re going to see new technologies and new applications for the foreseeable future. So, in that respect, RFID won’t “arrive” for quite some time.

What I want to talk about is the current evolution and the hype that may get attached to it.

A report recently published by IDTechEx examines smart labels and makes particular note of “chipless” RFID tags. Chipless tags, as you might suppose, do not contain silicon chips (aka integrated circuits or ICs). Instead, they rely on thin film, magnetic resonance, fine wires and other methods to generate unique signal patterns discernible by a suitable reader.

The advantages of a “chipless” tag should be obvious: a) much lower cost, and b) improved flatness/thinness. Even with all the recent and foreseeable advances in silicon chip design and manufacture, chip-based tags are still relatively expensive. Further, the chips do produce a distinct “bump” in labels. When printing labels, that “bump” has to be factored into the label design and, where space is tight, this can present some challenges.

The “hype” that may become associated with chipless tags is that they are destined to replace the current generation of smart labels. This may be true in some closed applications but it would be a gross overstatement of current chipless tag capabilities.

The chipless tags that are available today do not carry “data” in the conventional sense. What they offer is a distinct response pattern that can be associated with a particular data structure. That is, a group of tags can be manufactured to return the same response pattern and that pattern or signal can be associated with a unique product number. Alternately, chipless tags can generate unique responses that can serve, in effect, as serial numbers.

How important is the distinction between a tag that carries data versus one that provides a response pattern?

If readers can be programmed to return a data string useful to the host system, it becomes transparent to the system and isn’t an issue. On the other hand, the logistics of distributing pattern-product ID matching tables could be a nightmare. The complexity of this task would likely outweigh the cost savings offered by chipless tags.

For serial numbers, it becomes even more problematic in any but a closed system. Since the pattern is simply unique to that item, distribution of massive look-up tables would be required for positive identification in an open system. In a closed system, or for some types of product validation, however, such tags could work quite well since they would be virtually impossible to counterfeit.

Although worth investigating for closed systems, these chipless technologies are not destined to take over the world any time soon.

A much more exciting prospect — one that will serve as a direct challenge to current-day smart labels — is just over the horizon (and possibly not too far over it).

The IDTechEx report highlights RFID labels employing “printed” circuits. That is, the components of an IC would be created using something like conventional, multi-color printing processes instead of the complex and delicate manufacturing process required in silicon IC production. This concept isn’t Buck Rogers stuff. It was demonstrated several years ago with the creation of transistors and other building blocks of circuitry, and a lot of development has gone on since then.

The size of the circuits, with current technology, is “huge” compared to silicon — but that’s not an issue here. An integrated RFID tag, complete with antenna, memory and all the other necessary components, would be relatively easy to fit on a conventional shipping label. Because the circuits are relatively simple and the real estate exists, RFID is likely to be one of the first beneficiaries of this technology once it’s perfected.

But for now, if someone tries to hype you on chipless tags, just pass the salsa.

For a review of the IDTechEx report, or to order the report, contact AIM Global, 634 Alpha Drive, Pittsburgh, PA 15238, (www.aimglobal.org/aimstore/idtechex.htm), or contact IDTechEx directly at www.idtechex.com/book2.html.

Bert Moore, contributing editor, [email protected]

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