RF characteristics of flexible circuits patterned with hybrid Ag paste

Kwang Ho Jung, Sang Woo Kim, Min Kyung Maeng, Dong Gun Kam, Seung Boo Jung

Research output: Contribution to journalArticlepeer-review


Printed electronics based on nanomaterials has been a potential alternative to conventional electronic technology and is favorable for flexible polymer substrates. However, a printed circuit has insufficient electrical performance and mechanical reliability under flexible stress. We designed hybrid Ag pastes containing Ag nanoparticles (NPs, 30–50 nm) and Ag flake (F, 2.5–3.5 μm in diameter) particles to overcome the obstacles of printed electronics. Six types of Ag paste (Ag NPs-x wt% F paste, x = 0, 10, 25, 50, 75, and 100) were screen-printed onto a polyimide substrate and sintered at 200 °C for fabricating a flexible circuit. We simulated a coplanar waveguide pattern before measuring the S-parameter using high frequency structural simulation. To investigate the radio frequency characteristics of various Ag circuits under sliding stress, a network analyzer and Cascade’s probe system in the frequency range from 1 to 10 GHz were employed before and after 100,000 sliding cycles. Hybrid Ag circuits showed stable electrical conductance and signal transmission, while pure Ag particle circuits showed a definite drop of electrical conductance (over 30% increase of electrical resistance) under cyclic sliding stress. The microstructural crack behavior demonstrated that the Ag F content within the Ag hybrid circuits effectively suppressed crack propagation, leading to improved flexibility of the sintered Ag circuit.

Original languageEnglish
Pages (from-to)5074-5081
Number of pages8
JournalJournal of Materials Science: Materials in Electronics
Issue number6
Publication statusPublished - 2018 Mar 1

Bibliographical note

Funding Information:
Acknowledgements This work was supported by “Human Resources Program in Energy Technology” of the Korea Institute of Energy Technology Evaluation and Planning (KETEP), granted financial resource from the Ministry of Trade, Industry & Energy, Republic of Korea (No. 20174030201800). This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (2017R1D1A1B03035587).

Publisher Copyright:
© 2017, Springer Science+Business Media, LLC, part of Springer Nature.

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Condensed Matter Physics
  • Electrical and Electronic Engineering


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