New Paper RFID Tag is Environmental-friendly by Being Chip- and Metal-Free

By Claire Swedberg

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Global brands will pilot a passive RFID tag from PulpaTronics that transmits a unique ID when interrogated, but without a chip or metal-based antenna.

Research out of the U.K. has led to a startup company—PulpaTronics—that is building a chip-free, paper RFID tag that leverages a carbon-based antenna that eliminates any use of metal. The passive RFID tag transmits between 1 and 4 GHz to specialized readers, and can be recycled with a product or packaging, since the tag is entirely paper.

By making a tag entirely out of paper, the company says it can streamline the manufacturing process thereby reducing the environmental footprint of RFID tag production.

In fact, PulpaTronics estimates its tags will reduce carbon dioxide emissions by 70 percent compared to standard RFID tags while halving the associated price for assembly.

Cutting out the waste

RFID tags, which are used in the billions today, inherently come with material that ends up in the waste stream.

The tags—which automatically identify products when built into price labels, for instance— are usually made of polyethylene terephthalate (PET) plastic. Increasingly, more environmentally-friendly tags are being produced with paper inlays that use metal components.

That’s a problem when it comes to recycling. Although most if not all parts of the tag can be recycled, the components would need to be separated.

Additionally, separation of each tag’s components isn’t financially viable for most companies. Therefore, says company cofounder and CEO Chloe So, “one of our big differentiators is that the tag is compatible with the existing paper recycling.”

Design Work at Royal College of Art

The development began with a group of design engineering graduates at London’s Royal College of Art and Imperial College London, who took on a project to reduce waste in single-use electronics. Since then, two members of that group–So and Barna Soma Biro, chief technology officer—launched PulpaTronics.

The new company, based in London, was established as a sustainability venture.

“We are design engineering students who were looking for a design challenge,” says So. As they began exploration of existing technologies, they chose RFID tags as a short-lived electronic circuits that is typically disposable, and therefore impacts the waste stream.

Building on Sustainability Efforts

The concept of chipless RFID tags is not new, nor is the laser-based, non-metal antenna that the company is using in its new tags. What is new that PulpaTronics may be the first company to leverage both innovations in a single passive RFID tag. It consists of a simple paper layer, with no adhesives, and a laser mark that acts as the antenna.

While some tag makers are printing RFID antennas onto paper inlays, (which eliminates the chemical-based etching process as well as aluminum material) there is still silver in the ink, So points out.

The PulpaTronics process uses only the paper itself and a laser to make its antenna.

“Paper is a substrate that contains carbon, when the laser makes contact with the paper it basically changes the chemical structure of the paper,” says Biro.

That means that the laser creates a carbonized, conductive circuit on the paper directly.

PulpaTronics Product

The group tackled the challenge related to chips which inherently include silicon or ceramics. To eliminate the chip, the researchers had to use a different approach for storing the unique ID of a tag.

Rather than encoding an ID number on a chip, they created a mechanism in which a geometrically unique pattern is applied, via laser, on each tag. The group is building a different reading and decoding process to extract that information from the antenna’s radio signal.

In the long term, the company expects that the tags could be produced in high volumes, each with its own unique pattern. Additionally, So says the antenna’s unique pattern could include a geometric shape that would indicate a category, such as a specific company that manufactured the tagged item.

For instance, if a retail brand wanted to create an ID specifically for its own products, versions could be created with geometric shapes of the antenna specific to that company.

Reading Modules for Real-world Settings

The tags use a different frequency than the commonly used UHF RFID tags. That means chipless tags do not respond to readers that interrogate at the UHF frequency.

“That’s a market challenge we’re tackling,” says So.

The solution could be a module that could be built into existing UHF RFID readers to interrogate the PulpaTronics tags simultaneously with UHF RFID tags.

“We’re looking into how to enhance readers,” So says. But the system could be used by companies that have not yet used RFID and therefore don’t require UHF RFID tag reading capabilities.

Keeping Price Down

The chipless tags would have a shorter read range than UHF tags and would not respond with the same speed as traditional tags, especially in a dense environment. The company estimates the read distance is 60 to 100 centimeters.

If many tagged goods were packed in a carton and they were read simultaneously, the reads could be challenging.  In fact, a bulk scan would typically be three to five items at a time. That would be considerably fewer than the thousands of tags that might be read with UHF readers as large volumes of tags move through a portal.

There are other potential advantages to the chipless tags though, in addition to sustainability. In the long term the company expects its tags to be less expensive that existing UHF tags.

“Traditionally the microchip is what is the most expensive part of the tag and the manufacturing process is shorter, with lower transportation costs,” said Biro.

Fewer Layers

While most RFID tags require an average of six layers, the PulpaTronics version could be built with fewer.

The company has validated the technology in a lab setting at Imperial College London and is now working to improve on geometric patterns, conduct stress testing and optimizing the paper material.

Several retail companies, which PulpaTronics declined to name, have offered to conduct pilots. Some are already utilizing RFID technology with UHF tags. More pilots or deployment might take place at the end of 2024.

The company is seeking partnerships, with So stating “it would be nice to get people interested, to help with our future funding opportunities.”

Key Takeaways:
  • Startup PulpaTronics had developed an all-paper RFID tag with laser-based antenna and no chip, to make single-use electronics sustainable.
  • The prototypes are still being tested, while several brands are planning to pilot the technology.