University of Oulu

Mater. Adv., 2022, 3, 1687-1694,

Wood-based composite materials for ultralight lens antennas in 6G systems

Saved in:
Author: Kokkonen, Mikko1; Nelo, Mikko1; Liimatainen, Henrikki2;
Organizations: 1Microelectronics Research Unit, University of Oulu, FI-90014, Oulu, Finland
2Fiber and Particle Engineering, University of Oulu, FI-90014, Oulu, Finland
3Center for Wireless Communications, University of Oulu, FI-90014, Oulu, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 4.5 MB)
Persistent link:
Language: English
Published: Royal Society of Chemistry, 2022
Publish Date: 2022-04-27


Extremely high frequencies used in future wireless communication systems such as 6G require low loss materials to avoid wasting power and maintain acceptable efficiency. Furthermore, especially in the internet of things (IoT) applications, low weight and the possibility to focus the radiation pattern in the desired direction would also improve the communication between units and reduce the required signal power. Radio frequency (RF) lenses for signal focusing can be made from low loss and low relative permittivity materials. In this work, the development of sustainable composites with a relative permittivity of ∼1.15 and loss tangents in the range of 10⁻³ is presented. The composites were fabricated at the exceptionally low temperature of 95 °C and were based on hollow micron-sized glass spheres and three different types of cellulose nanofibers as the water-soluble binder. A simple manufacturing method through casting and drying is presented. The surface properties of the composites were investigated with surface profile analysis and the dielectric properties by SPDR and terahertz spectroscopy. The weight of the fabricated lens was 0.6 g and the transmittance was 99.85%. The lens improved the antenna gain by 14–18 dBi depending on the surface smoothening. Also, coating the lens with a moisture protecting agent did not alter the lens performance.

see all

Series: Materials advances
ISSN: 2633-5409
ISSN-E: 2633-5409
ISSN-L: 2633-5409
Volume: 3
Pages: 1687 - 1694
DOI: 10.1039/D1MA00644D
Type of Publication: A1 Journal article – refereed
Field of Science: 213 Electronic, automation and communications engineering, electronics
215 Chemical engineering
216 Materials engineering
Funding: This work was supported partly by Academy of Finland 6Genesis Flagship (Grant no. 318927) and partly by European Regional Development Fund project: Novel digitally fabricated materials for electronics, optics and medical applications (NOVIDAM).
Academy of Finland Grant Number: 318927
Detailed Information: 318927 (Academy of Finland Funding decision)
Copyright information: © The Author(s) 2022. This article is licensed under a Creative Commons Attribution 3.0 Unported Licence.