Impact of Complex Permeability Measurements up to Millimeter-Wave Frequency Range

S. Yabukami, K. Nozawa, L. Tonthat, K. Okita, R. Sai

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)


A highly sensitive microstrip-line-type probe using a flexible substrate was developed to measure thin-film permeability continuously up to the millimeter-wave frequency range (over 30 GHz). The probe enables broad bandwidth and highly sensitive permeability measurements without sample size limitations. The complex permeability of the CoFeB film (45 mm ×25 mm and 0.5μm in thickness), CoNbZr film (25 mm ×25 mm and 3 nm in thickness), and nickel ferrite film (8 mm ×5 mm, and 1.2μm in thickness) were optimized. The measured permeability spectrum and ferromagnetic resonance frequency showed good agreement with the theoretical values based on the Landau-Lifshitz-Gilbert equation and eddy current generation up to 67 GHz.

Original languageEnglish
Article number9149663
JournalIEEE Transactions on Magnetics
Issue number2
Publication statusPublished - 2021 Feb


  • Complex permeability measurement
  • magnetic thin film
  • microstrip-line-type probe
  • millimeter-wave
  • sample size limitation


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