Stretchy Circuits Foretell Future of Wearable Electronics

A new wave of wearable integrated circuits could drive the Internet of Things (IoT) and a much more connected, high-speed wireless world.

Developed by researchers at the University of Wisconsin (WISC; Madison, USA) and the University of Electronic Science and Technology (UESTC; Chengdu, China), the powerful, stretchable, highly efficient integrated epidermal electronic circuits could allow health care staff in an intensive care unit (ICU) to monitor patients remotely and wirelessly. What makes the stretchable integrated circuits powerful is their unique structure, which contains, essentially, two ultra-tiny intertwining power transmission lines in repeating S-curves.

The serpentine shape, formed in two layers with segmented metal blocks, like a three dimensional (3D) puzzle, gives the transmission lines the ability to stretch without affecting their performance. It also helps shield the lines from outside interference while confining the electromagnetic waves flowing through them, resulting in an almost complete elimination of current loss. The advance could allow health care staff to monitor patients remotely and wirelessly, increasing patient comfort by decreasing the customary tangle of cables and wires.

Unlike other stretchable transmission lines, whose widths can approach 640 micrometers (0.64 millimeters), the new stretchable integrated circuits are just 25 micrometers (0.025 millimeters) thick, and can operate at radio frequency levels up to 40 gigahertz, a microwave frequency range that falls directly in the 5G range, which is slated to accommodate a growing number of cellphone users that can provide notable increases in data speeds. The study was published on May 27, 2016, in Advanced Functional Materials.

“This is a platform; this opens the door to lots of new capabilities. We’ve found a way to integrate high-frequency active transistors into a useful circuit that can be wireless,” said senior author Professor Zhenqiang “Jack” Ma, PhD, the University of Wisconsin. “These concepts form the basic elements used in the design of stretchable microwave components, circuits, and subsystems performing important radio frequency functionalities, which can apply to many types of stretchable bioelectronics for radio transmitters and receivers.”

Related Links:
University of Wisconsin
University of Electronic Science and Technology