Page 112 - IJB-9-4

International Journal of Bioprinting

RESEARCH ARTICLE
An inkjet-printed bendable antenna for wearable

electronics

Hang Yu 1,2† , Xingguo Zhang , Hao Zheng , Dachao Li , Zhihua Pu *
1
1†
1
1
1 State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University,
Tianjin, China
2 School of Instrumentation and Optoelectronic Engineering, Beihang University, Beijing, China

Abstract
Flexible antennas, which can conform to the skin and transfer signals to terminals,
are particularly useful for wearable electronics. Bending, which frequently occurs
to flexible devices, significantly affects the performance of flexible antennas. Inkjet
printing has been used as an additive manufacturing technology for fabricating
flexible antenna in recent years. However, there is little research on the bending
performance of inkjet printing antenna in both simulation and experiment. This
paper proposes a bendable coplanar waveguide antenna with a small size of 30
× 30 × 0.05 mm by combining the advantages of fractal antenna and serpentine
3
antenna, which realizes the ultra-wideband feature and avoids the problems of
large dielectric layer thickness (greater than 1 mm) and large volume of traditional
microstrip antenna at the same time. The structure of the antenna was optimized
by simulation using the Ansys high-frequency structure simulator, and the antenna
was fabricated on a flexible polyimide substrate by inkjet printing. The experimental
characterization results show that the central frequency of the antenna is 2.5 GHz,
† These authors contributed equally
to this work. the return loss is −32 dB, and the absolute bandwidth is 850 MHz, which is consistent
with the simulation results. The results demonstrate that the antenna has anti-
*Corresponding author: interference capability and can meet the ultra-wideband characteristics. When the
Zhihua Pu (puzhihua@tju.edu.cn)
traverse and longitudinal bending radius are greater than 30 mm and skin proximity
Citation: Yu H, Zhang X, Zheng H, greater than 1 mm, the resonance frequency offsets are mostly within 360 MHz, and
et al., 2023, An inkjet-printed
bendable antenna for wearable return losses of the bendable antenna are within the −14 dB compared with the
electronics. Int J Bioprint, 9(4): 722. no bending condition. The results exhibit that the proposed inkjet-printed flexible
https://doi.org/10.18063/ijb.722 antenna is bendable and promising for wearable applications.
Received: December 27, 2022
Accepted: February 07, 2023
Published Online: March 29, 2023 Keywords: Flexible antenna; Bendable antenna; Coplanar waveguides; Inkjet
printing
Copyright: © 2023 Author(s).
This is an Open Access article
distributed under the terms of the
Creative Commons Attribution
License, permitting distribution 1. Introduction
and reproduction in any medium,
provided the original work is Flexible wearable electronics is a research hotspot in the biomedical field [1-6] , and a
properly cited. flexible antenna that can conform to the skin is a critical component [7,8] . Flexible antenna
Publisher’s Note: Whioce can be used for communication between electronic devices attached to the outer surface
Publishing remains neutral with of human skin and personal wireless terminals [9,10] . With the advent of 5G technology,
regard to jurisdictional claims in
published maps and institutional the rapid development of wireless communication technology, and the increasingly
affiliations. extensive application of wearable devices in daily life, there are stricter requirements

Volume 9 Issue 4 (2023) 104 https://doi.org/10.18063/ijb.722