Wireless sensor detects trace amounts of key IED ingredient

According to a statement, the device — which employs carbon nanotubes and is printed on paper or paper-like material using standard inkjet technology — could be deployed in large numbers to warn of the presence of improvised explosive devices (IEDs).

‘This prototype represents a significant step toward producing an integrated wireless system for explosives detection,’ said Krishna Naishadham, a principal research scientist who is leading the work at the Georgia Tech Research Institute (GTRI). ‘It incorporates a sensor and a communications device in a small, low-cost package that could operate almost anywhere.’

Other types of hazardous gas sensors are based on semiconductor fabrication and gas chromatography, Naishadham said, and they consume more power, require human intervention and typically do not operate at ambient temperatures. Furthermore, those sensors have not been integrated with communication devices such as antennas.

The wireless component for communicating the sensor information — a resonant lightweight antenna — was printed on photographic paper using inkjet techniques devised by Prof Manos Tentzeris of Georgia Tech’s School of Electrical and Computer Engineering. Tentzeris is collaborating with Naishadham on development of the sensing device.

The sensing component, based on functionalised carbon nanotubes (CNTs), has been fabricated and tested for detection sensitivity by GTRI research scientist Xiaojuan Song.

This is not the first inkjet-printed ammonia sensor that has been integrated with an antenna on paper, said Tentzeris. His group produced a similar integrated sensor last year.

‘The fundamental difference is that this CNT sensor possesses dramatically improved sensitivity to minuscule ammonia concentrations,’ Tentzeris said. ‘That should enable the first practical applications to detect trace amounts of hazardous gases in challenging operational environments using inkjet-printed devices.’