Highly stretchable, deformation-stable wireless powering antenna for wearable electronics

Abstract

Near-field communication (NFC) antennas, which use electromagnetic coupling technology to realize wireless transmission and energy harvesting over short distances, are widely used in wearable and implantable electronics. However, mechanical deformations are inevitable in practical applications, which usually have serious effects on their resonant frequency and quality factor, resulting in communication failure. Here, we report a highly stretchable, deformation-stable NFC antenna (SDNA) based on a spider-web structure and liquid-metal microchannels. Results of the finite element analysis and experimental tests suggest that the proposed antenna is insensitive to tensile loading and has smaller inductance variation and resonance frequency shift. The antenna frequency is only offset by 2.75 MHz with a strain of 300 %. Its robustness and stability are verified under diverse circumstances, including folding (0–170°), bending (2.5–20 mm), twisting (0–270°), rolling (0–360°), overall pressure (1000 kPa), and cyclic stretching (5000 times). Its resonant frequency remains still stable when mounted on a contracting and expanding balloon or the moving knee joints (0–9 km/h). Based on its excellent stretchability and stability, the proposed SDNA is ideal to be used for wearable electronics, such as smart clothing. In summary, the proposed antenna has considerable potential for applications in wearable and implantable electronics.