RF-enabled intrinsic wireless temperature sensing. Credit: Mahmoud Wagih et al.
University of Glasgow researchers have developed a novel temperature sensor that utilizes a flexible “smart skin” and electromagnetic waves that do not require battery power or onboard processing. The sensors operate over a much larger temperature range than traditional thermistors.
Comprised of a carbon fiber composite and silicon rubber, the novel sensors operate by absorbing or reflecting RF signals at variable rates depending on atmospheric temperature. The sensor is capable of withstanding thousands of bending or stretching cycles without sensitivity loss across a larger temperature range than previously possible.
Published in Nature Communications, eliminates the need for the numerous thermistors needed in traditional temperature sensors requiring detection across a wide range of temperatures. The novel sensor created by the researchers offers a record-breaking range from 30°C to more than 200°C. To construct the sensor, researchers utilized 3D printing to mold the material and embed numerous components such as antennas, RFID labels, and resonators.
"Sensors are the main interface between the analog world and smart devices,” said Dr. Mahmoud Wagih, Lecturer at the University of Glasgow. “To communicate real-world changes in measurements like temperature or humidity to wireless smart devices, those measurements first need to be digitized. We designed a simple soft composite using common silicone and carbon fibers, which can be easily molded into any shape. These skin-like substrates could be used to design antennas over large areas, which can then radiate signals that are highly sensitive to temperature changes. Many researchers have used RF and microwave devices to measure liquid formulations, temperature, humidity, and other physical and chemical parameters. However, this level of sensitivity has not been demonstrated before."
The novel sensors created by the researchers could lead to cheaper and more sustainable wireless sensors as fewer thermistors will be required to sense over a wide temperature range. Dr. Wagih is currently building on these findings with hopes of discovering and developing additional sustainable wireless electronics. "We are delighted to start further research on functional and natively stretchable materials for body-centric wireless sensing, building on our track record in cutting-edge RF sensing,” added Dr. Wagih.