Researchers from the Massachusetts Institute of Technology (MIT) have developed a microchip identification tag that works with terahertz waves to offer a more secure verification method than traditional radio frequency identification (RFID) tags. Terahertz waves are smaller in wavelength, yet much higher in frequency than radio waves, which make the tag more difficult to clone or tamper with.
While the tags developed in the previous research were tiny, cheap, and provided improved security over RFIDs, they could still be peeled off an authentic product and attached to a counterfeit product. This led the researchers to develop an anti-tampering feature.
The new development involves using the glue that attaches the tag to products as an authentication medium. The adhesive is mixed with microscopic metal particles that create a unique pattern, similar to a fingerprint, when the tag is stuck onto a product. The metal particles are akin to tiny mirrors for terahertz waves. When the waves encounter the pattern, they reflect uniquely, depending on the size, position, and orientation of the particles, creating a one-of-a-kind reflected pattern.
If someone attempts to peel the tag off and reattach it to a different product, the unique pattern is destroyed, providing a solid defense against counterfeiting attempts. A light-powered anti-tampering tag of this type, about 4 square millimeters in size, has been shown to detect similar glue pattern fingerprints with an accuracy of more than 99%, with the assistance of a machine-learning model.
Given the small footprint and low production cost, the terahertz tag could be used in large-scale supply chains, including on items that are too small to accommodate traditional RFIDs (e.g., some medical devices). Due to their short wavelength, terahertz waves have high levels of loss during transmission. This feature limits the distance between the sensor and the tag to about 4 centimeters for an accurate reading. The team plans to overcome these limitations, hoping that their work can broaden the applications of the terahertz spectrum in diverse areas such as identification, security, and contraband detection. The research was supported partially by the U.S. National Science Foundation and the Korea Foundation for Advanced Studies.
