Screen-printed 1 x 4 Quasi-Yagi-Uda Antenna Array on Highly Flexible Transparent Substrate for the Emerging 26 GHz Band 5G Applications

In the Internet of Things (IoT) era, the demand for cost-effective, flexible, wearable antenna and circuits has become very high. Accordingly, screen printing techniques are becoming more popular due to their lower costs and high-volume manufacturing abilities. This paper presents and investigates a full-screen printed 1 x 4 Quasi-Yagi-Uda antenna array on a high-transparency flexible Zeonor thin-film substrate for emerging 26 GHz band 5G applications. As part of this study, screen printing implementation rules are developed by properly managing ink layer thickness on a transparent flexible Zeonor thin-film dielectric to achieve a decent antenna array performance. In addition, a screen-printing repeatability study has been carried out through a performance comparison of 24 antenna array samples manufactured by our research partner from CEA-Liten Grenoble. Despite the challenging antenna array screen-printing at higher frequencies, the measured results show a good antenna performance as anticipated from the traditional subtractive printed circuit board (PCB) manufacturing process using standard substrates. It shows a wideband matched input impedance from 22-28 GHz and a maximum realized gain of 12.8 dB at 27 GHz.