The development could provide a platform for manufacturers seeking to expand the capabilities and applications of wearable electronics
A team of university engineers in the US has created what claims to be the world’s fastest stretchable, wearable integrated circuits, which could be used to advance the development of the Internet of Things. The researchers explain that the technology could be used in wearable electronics that adhere to the skin like temporary tattoos.
The research project is being led by Zhenqiang ’Jack’ Ma, the Lynn H Matthias Professor in Engineering and Vilas Distinguished Achievement Professor in electrical and computer engineering at the University of Wisconsin-Madison. The applications could include those aimed at the biomedical sector. For example, the integrated circuits could be used for epidermal electronic systems that allow health care staff to monitor patients remotely and wirelessly.
The structure of the stretchable integrated circuits was inspired by twisted pair telephone cables. Essentially, they contain two tiny intertwining power transmission lines in repeating S-curves. This serpentine shape -- formed in two layers with segmented metal blocks, like a 3-D puzzle -- gives the transmission lines the ability to stretch without affecting their performance. It also helps shield the lines from outside interference and confine the electromagnetic waves flowing through them, almost completely eliminating current loss.
Currently, the researchers’ stretchable integrated circuits can operate at radio frequency levels up to 40 gigahertz. Unlike other stretchable transmission lines, whose widths can approach 640 micrometers (or .64 millimeters), the new stretchable circuits are just 25 micrometers (or .025 millimeters) thick.
Ma’s group has been developing ‘transistor active devices’ for the past decade and the latest advance combines the researchers’ expertise in both high-frequency and flexible electronics.
“We’ve found a way to integrate high-frequency active transistors into a useful circuit that can be wireless,” says Ma, whose work was supported by the Air Force Office of Scientific Research. “This is a platform. This opens the door to lots of new capabilities.”
Other authors on the research paper include Yei Hwan Jung, Juhwan Lee, Namki Cho, Sang June Cho, Huilong Zhang, Subin Lee, Tong June Kim and Shaoqin Gong of UW–Madison and Yijie Qiu of the University of Electronic Science and Technology of China.