Researchers Developed a Chipless Alternative to Temperature-Sensing RFID Tags for Greener Packaging
Made using capacitive-doped PDMS, these sensors should cost less and be more environmentally friendly than RFID chips.
Researchers from the James Watt School of Engineering at the University of Glasgow have developed what they claim is a more sustainable form of sensor-equipped electronic tag, equivalent to a radio frequency identification (RFID) chip — only without the chip.
"Developing wireless sensing tags is crucial for monitoring temperature across supply chains, particularly in food safety and medical applications. By eliminating the need for microchips, these chipless tags could significantly reduce both cost and electronic waste compared to traditional RFID sensors," claims corresponding author Mahmoud Wagih, PhD, of the team's work. "While there have been various efforts in recent years to develop chipless smart devices, many require expensive specialized equipment for readout, limiting their potential in commercial applications. Our paper shows how multiple temperature sensors can be read simultaneously using an inexpensive portable device, which could make it an attractive prospect for adoption by a wide range of industries."
"The new technology we've developed uses materials which are cheap and widely-available, and the tags can be manufactured using a simple, scalable process," adds co-author Benjamin King, PhD, of the approach taken by the research team. "Our hope is that those unique characteristics could help the technology become widely-adopted in the years to come, helping to reduce the environmental harms currently being caused by single-use RFID tags."
The team's tags are based on a material called polydimethylsiloxane (PDMS) loaded with conductive fillers including copper, graphite, and milled carbon fibers to around 10 percent of its volume. In addition to being able to store data for remote retrieval using a wireless reader costing under $125, the tags can sense temperatures from 20-110° (68-230°F) with particular sensitivity up to 60°C (140°F) — making them, the team says, well-suited for "smart packaging" designed to ensure the safety of food products. Better still, they're quick to read with multiple tags being able to communicate with a single reader simultaneously — tested up to three tags, at varying distances, in the lab.
The researchers' work has been published in the journal Advanced Science under open-access terms.