Application of permanent magnet materials to microwave absorbers

Satoshi Sugimoto, Toshio Kagotani, Toru Maeda

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)


Recently, the use of microwaves in the GHz range has increased because of the demand for large data transmission. However, the problem of electromagnetic interference (EMI) has become serious, and much attention has been paid to microwave absorption materials. We have investigated magnetic loss of permanent magnet materials at natural resonance frequency, and have succeeded in the development of microwave absorbers using M-type (or W-type ferrite) and RE-Fe-B (RE: rare earth) compounds. The resonance frequency can be controlled by substitution of Fe3+ ion with other metal ion in the M-type or W-type ferrite. The resin composite of M-type ferrite shows wide bandwidth, in which the reflection loss (R.L.) is less than -20 dB. In the RE-Pe-B compounds, the substitution of RE with Sm or the fabrication of nanocomposite with a soft magnetic phase is effective method for controlling their resonance phenomena and functional frequency as microwave absorbers. The powder with fine α-Fe structure, which is produced by the disproportionation reaction of RE-Fe compounds, is useful for the filler of resin composite microwave absorbers in several GHz range.

Original languageEnglish
Pages (from-to)251-257
Number of pages7
JournalFuntai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy
Issue number3
Publication statusPublished - 2006 Mar


  • Electromagnetic compatibility (EMC)
  • Electromagnetic interference (EMI)
  • Microwave absorber
  • Reflection loss
  • Resonance frequency

ASJC Scopus subject areas

  • Mechanical Engineering
  • Industrial and Manufacturing Engineering
  • Metals and Alloys
  • Materials Chemistry


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