University of Oulu

M. Kokkonen, P. S. Pálvölgyi, R. Sliz, H. Jantunen, K. Kordas and S. Myllymäki, "An Ultralow-Loss and Lightweight Cellulose-Coated Silica Foam for Planar Fresnel Zone Plate Lens Applications in Future 6G Devices," in IEEE Antennas and Wireless Propagation Letters, vol. 22, no. 1, pp. 99-103, Jan. 2023, doi: 10.1109/LAWP.2022.3203434

An ultralow-loss and lightweight cellulose-coated silica foam for planar Fresnel zone plate lens applications in future 6G devices

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Author: Kokkonen, Mikko1; Pálvölgyi, Petra S.1; Sliz, Rafal2;
Organizations: 1Microelectronics Research Unit, Faculty of Information Technology and Electrical Engineering, University of Oulu, FI-90014 Oulu, Finland
2Optoelectronics and Measurement Techniques Unit, Faculty of Information Technology and Electrical Engineering, University of Oulu, FI-90014 Oulu, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 1.4 MB)
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Language: English
Published: Institute of Electrical and Electronics Engineers, 2022
Publish Date: 2023-01-10


Several passive components of fifth-generation (5G) and future sixth-generation (6G) telecommunication devices require substrate materials of very low dielectric permittivity and losses to avoid wave absorption, reflection, and interference. Apart from their dielectric properties, these materials shall be also affordable and sufficiently robust to enable postprocessing and integration of functional electrical components. Herein, we demonstrate a Fresnel zone plate lens for operation at 300 GHz, whose structure is supported on substrate made of an ultraporous silica foam with a nanocellulose thin film coating. The effective dielectric permittivity and loss of the substrate ( ϵ r = 1.018 ± 0.003 and tan δ < 3 × 10 −4 at 300 GHz) is close to that of air. Experiments show that the fabricated Fresnel zone plate lens connected to a waveguide with total gain of 20 dB and angular beamwidth of 2.9° in good agreement with microwave simulations. The proposed lens structure has additional advantages such as small volume, ultralight weight, and simulations indicate 60 GHz bandwidth making it particularly appealing for radio front-ends of future 6G devices.

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Series: IEEE antennas and wireless propagation letters
ISSN: 1536-1225
ISSN-E: 1548-5757
ISSN-L: 1536-1225
Volume: 22
Issue: 1
Pages: 99 - 103
DOI: 10.1109/lawp.2022.3203434
Type of Publication: A1 Journal article – refereed
Field of Science: 213 Electronic, automation and communications engineering, electronics
216 Materials engineering
Funding: This work was supported by the 6G Flagship of the Academy of Finland under Grant 346208.
Academy of Finland Grant Number: 346208
Detailed Information: 346208 (Academy of Finland Funding decision)
Copyright information: © The Author(s) 2022. This work is licensed under a Creative Commons Attribution 4.0 License. For more information, see