title: Tape transfer printing of a liquid metal alloy for stretchable RF electronics.
abstract: In order to make conductors with large cross sections for low impedance radio frequency (RF) electronics, while still retaining high stretchability, liquid-alloy-based microfluidic stretchable electronics offers stretchable electronic systems the unique opportunity to combine various sensors on our bodies or organs with high-quality wireless communication with the external world (devices/systems), without sacrificing enhanced user comfort. This microfluidic approach, based on printed circuit board technology, allows large area processing of large cross section conductors and robust contacts, which can handle a lot of stretching between the embedded rigid active components and the surrounding system. Although it provides such benefits, further development is needed to realize its potential as a high throughput, cost-effective process technology. In this paper, tape transfer printing is proposed to supply a rapid prototyping batch process at low cost, albeit at a low resolution of 150 μm. In particular, isolated patterns can be obtained in a simple one-step process. Finally, a stretchable radio frequency identification (RFID) tag is demonstrated. The measured results show the robustness of the hybrid integrated system when the tag is stretched at 50% for 3000 cycles.
authors.affiliation: The Angstrom Laboratory, Department of Engineering Sciences, Uppsala University, Box 534, Uppsala 75121, Sweden. seunghee.jeong@angstrom.uu.se.
authors.forename: Seung Hee
authors.initials: SH
authors.lastname: Jeong
authors.affiliation: The Angstrom Laboratory, Department of Engineering Sciences, Uppsala University, Box 534, Uppsala 75121, Sweden. klas.hjort@angstrom.uu.se.
authors.forename: Klas
authors.initials: K
authors.lastname: Hjort
authors.affiliation: The Angstrom Laboratory, Department of Engineering Sciences, Uppsala University, Box 534, Uppsala 75121, Sweden. zhigang.wu@angstrom.uu.se.
authors.forename: Zhigang
authors.initials: Z
authors.lastname: Wu