IEEE Journal of Microwaves (Jan 2023)

Flexible Lumped Microwave Passive Components and Filters on Cellulose Nanofibril Substrates

  • Shuoyang Qiu,
  • Huilong Zhang,
  • Qiangu Yan,
  • Linda Katehi,
  • Shaoqin Gong,
  • Zhiyong Cai,
  • Zhenqiang Ma

DOI
https://doi.org/10.1109/JMW.2022.3206715
Journal volume & issue
Vol. 3, no. 1
pp. 96 – 101

Abstract

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Cellulose nanofibril (CNF) substrates that are inexpensive, biodegradable, and quickly incinerable, are potential substrates for disposable RF applications. In this paper, high-performance flexible microwave lumped elements and filters fabricated on flexible CNF substrates are reported. A spiral inductor with a resonance frequency of 29.8 GHz and quality (Q) factor of 8.5 and a metal-insulator-metal (MIM) capacitor with a resonance frequency of 45 GHz and Q factor of 85.2 were achieved in a 200 μm thick CNF substrate. Meanwhile, the inductor and capacitor exhibit outstanding mechanical bendability, that is negligible performance changes were observed when they were bent to a radius as small as 15 mm. Based on the spiral inductor and MIM capacitor, a 5-GHz band-stop filter and a 4 GHz band-pass filter with excellent mechanical bendability were further demonstrated on the CNF substrate. These results indicate the potential of using CNF as substrates for broader microwave applications.

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