Multi-Field Invisible Sensor Built by Engineering Team


Researchers from the National University of Singapore (or NUS) have created an innovative camouflage technique that hides both thermal and electronic sensors without limitations on performance.

The team was led by Assistant Professor Qiu Cheng-Wei from the Department of Electrical & Computer Engineering at NUS Faculty of Engineering, the researchers built the first multifunctional camouflage case that is able to make sensors undetectable in thermal and electronic surroundings.

Technologies that are currently used today make sensors undetectable but also aren’t very effective. Some also can only work in specific physical fields, such as just thermal or only electrical situations. During the past ten months, the NUS team has been experimenting with demonstrations that are able to hide sensors in both physical fields. These undetectable sensors are also able to look deeper into the surrounding environment while remaining inconspicuous.

Prof Qiu holding pieces coated with the shell material. (Image credits: ALICIA CHAN)

Assistant Professor Qui says the team has built a camouflage shell that copies thermal and electric fields at the exact same time. The substance being camouflaged becomes completely veiled as the shape and position are unable to be perceived within thermal and electric images.

During the latest experiment, the researchers created an optimal invisible sensor by masking it with a thin shell made of pure copper. The shell was built to greatly reduce the perturbation of heat flux and electric currents at the same time. The shell’s thickness was formulated based on in-depth calculations in order to allow explicit manipulation of external multi-physical fields to shield the sensor, rendering it obscured but still keeping its ability to receive incoming signals from the exterior.

Dr. Qiu says their camouflaging shell will open up a whole new avenue for advanced sensing and security systems. Normally, sensors that are used in the observation of current and heat flow in high voltage or strong temperatures are typically damaged quite easily. However, the team’s camouflaging shell protects sensors from dangerous environments while also improving accuracy. The shell actually eliminates distortions that may surround the sensor. The team says such a trait is significant in the study of other applications, like using a camouflaging shell on special mission fieldtrips. Researchers are currently working on developing invisible sensors that offer multiple functions and can rapidly become stealth.

invisible sensor
A sensor coated with the shell material is situated between a cold water tank and a heated plate. The sensor’s thermal energy is hidden due to the shell, which blends it with the thermal energy of the surroundings. (Image credits: Alicia Chan)

Researchers were inspired by the real-life chameleon in developing their novel camouflaging shell. The skin of the critter is made up of multiple layers of specialized cells that hold a range of pigments, with a transparent outer layer. Cells underneath the skin change color based on light intensity as well as temperature, and even when the mood of the Chameleon changes. The team has in effect created a new “skin” for the chameleon that will allow it to become invisible when it is in front of a thermal or electric signal detector.