University of Oulu

Pálvölgyi, P.S., Sebők, D., Szenti, I. et al. Lightweight porous silica foams with extreme-low dielectric permittivity and loss for future 6G wireless communication technologies. Nano Res. 14, 1450–1456 (2021).

Lightweight porous silica foams with extreme-low dielectric permittivity and loss for future 6G wireless communication technologies

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Author: Pálvölgyi, Petra S.1; Sebők, Daniel2; Szenti, Imre2;
Organizations: 1Microelectronics Research Unit, Faculty of Information and Electrical Engineering, University of Oulu, P. O. Box 4500, FI-90570, Oulu, Finland
2Interdisciplinary Excellence Centre, Department of Applied and Environmental Chemistry, University of Szeged, Rerrich Béla tér 1, H-6720 Szeged, Hungary
3Centre for Wireless Communications, University of Oulu, P. O. Box 4500, FI-90570 Oulu, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 2.5 MB)
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Language: English
Published: Springer Nature, 2021
Publish Date: 2021-03-11


In the next generation wireless communication systems operating at near terahertz frequencies, dielectric substrates with the lowest possible permittivity and loss factor are becoming essential. In this work, highly porous (98.9% ± 0.1%) and lightweight silica foams (0.025 ± 0.005 g/cm³), that have extremely low relative permittivity (εr = 1.018 ± 0.003 at 300 GHz) and corresponding loss factor (tan δ< 3 × 10⁻⁴ at 300 GHz) are synthetized by a template-assisted sol-gel method. After dip-coating the slabs of foams with a thin film of cellulose nanofibers, sufficiently smooth surfaces are obtained, on which it is convenient to deposit electrically conductive planar thin films of metals important for applications in electronics and telecommunication devices. Here, micropatterns of Ag thin films are sputtered on the substrates through a shadow mask to demonstrate double split-ring resonator metamaterial structures as radio frequency filters operating in the sub-THz band.

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Series: Nano research
ISSN: 1998-0124
ISSN-E: 1998-0000
ISSN-L: 1998-0124
Issue: 5
Pages: 1450 - 1456
DOI: 10.1007/s12274-020-3201-2
Type of Publication: A1 Journal article – refereed
Field of Science: 221 Nanotechnology
Funding: The financial support received partly from EU Interreg Nord-Lapin liitto (project Transparent, conducting and flexible films for electrodes), Academy of Finland (6Genesis Flagship under Grant 318927), University of Oulu (projects Entity and PoC: Ultra-low permittivity and loss porous nanocomposites for future 6G telecommunication), Hungarian National Research, Development and Innovation Office through the projects GINOP-2.3.2-15-2016-00013 and GINOP-2.3.3-15-2016-00010, and the Ministry of Human Capacities, Hungary, grant 20391-3/2018/FEKUSTRAT is acknowledged. D. S. is thankful for the János Bolyai Research Scholarship of the Hungarian Academy of Sciences. Open access funding provided by University of Szeged.
Academy of Finland Grant Number: 318927
Detailed Information: 318927 (Academy of Finland Funding decision)
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