Innovative strain sensor design enables extreme sensitivity

A simple new design for a passive wireless strain sensor offers unprecedented sensitivity while being thin enough to be embedded within structures without causing defects^[1]. With further development, the KAUST team expects that the chipless design could be adapted to make sensors that respond to other stimuli, such as the temperature or chemical environment.

The design combines several existing technologies into a very efficient package. “The advantage in terms of sensitivity comes from merging different physics for two different responses from two materials,” explains Hassan Mahmoud, a doctoral researcher in the team of Gilles Lubineau, who led the study.

The sensor is printed with inks that change their electrical resistance in response to strain. The ink is printed in such a way as to create a circuit with capacitive domains, enabling the sensor to be activated wirelessly by a specific frequency. The circuit is designed to make the activation frequency very sensitive to stimulation, so it reflects the amount of strain the sensor is under.

Manufacturing the new sensor should be quick and easy. “Our mechanism uses simple available materials and techniques, so it is suitable and scalable for use by industry,” says Mahmoud.

The design might have to be adjusted depending on the use case, but Mahmoud does not expect that to be challenging. “The R&D is done, so it is just about customizing it to be suitable to the application, like using a substrate that’s right for wearables or that can withstand the high temperatures in structural manufacturing,” he explains.

Mahmoud, a mechanical engineer, explains that the sensor was developed in response to engineers’ needs. “We have lots of challenges when it comes to inspecting or monitoring structures during operations, especially with composite materials, which are very sensitive to having sensors embedded,” he says. But the new sensor is thin enough that it could even be used in composites.

He sees a wide range of potential applications for the new sensor. “It can be used in industrial applications, such as aerospace structures, oil and gas rigs, and many other structures that need real-time monitoring, like bridges. The technology can also be used for wearables, for example, to monitor the movement of muscles in sports or to track relevant health indicators,” he says.

Lubineau outlines how further work will open even more applications. “With additional research, we can tune the architecture that we invented to design sensors for other types of stimuli, like the chemical environment. We can build a full portfolio of sensors using the same physical principles,” he explains.

Reference

1. Mahmoud, H.A., Nesser, H., Mostafa, T.M., Ahmed, S., Lubineau, G. A fully printable strain sensor enabling highly-sensitive wireless near-field interrogation. Advanced Science 2025, 2411346 | article.