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

• 作 者: Petra S.Pálv(o)lgyi Daniel Seb(o)k Imre Szenti Eva Bozo Henri Ervasti Olli Pitk(a)nen Jari Hannu Heli Jantunen Marko E.Leinonen Sami Myllym(a)ki Akos Kukovecz Krisztian Kordas
• 机 构: Microelectronics Research Unit,Faculty of Information and Electrical Engineering,University of Oulu,
• 出 处: 纳米研究（英文版）
• 发表日期: 2021年5期
• 关键词: low-permittivity materials low-loss dielectrics templated sol-gel synthesis sili

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 (εt =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,micropattems 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.