They look like mini-Rorschach tests, but quick response (QR) codes are powerful barcode tracking tools. Now, the pixilated, black square grid offers an added tracking dimension: signal transmission and detection. The antenna capability was developed by researchers at the Center for Security Printing & Anti-Counterfeiting Technology, supported in part by NSF's Experimental Program to Stimulate Competitive Research (EPSCoR).

This research provides another level of security to sensitive materials because the QR antennas are hard to detect and replicate. By requiring transmission of a key signal, the antenna offers robust security. Without a key signal, the code could be counterfeit. The added security supplied by antennas could help reduce the multi-billion-dollar expense incurred annually by governments and private industry as a result of counterfeiting.

The antenna works at 2.4 gigahertz and has omnidirectional radiation, demonstrating its strong receiver capabilities. The antennas can be used as an additional security feature and/or replacement for radio frequency identification tag antennas.

The QR code is a type of matrix 2-D barcode that was first utilized in the automotive industry in Japan and later became popular in other commercial products. The code appears as a 2-D image that can be scanned and recognized by a camera, personal cellphone or other imaging device and can be translated into a text message, phone number or web address.