A simple method for measuring the relative permittivity of printed circuit board materials

Akihiro Namba, Osami Wada, Yoshitaka Toyota, Yukihiro Fukumoto, Zhi Liang Wang, Ryuji Koga, Takuya Miyashita, Tetsushi Watanabe

Research output: Contribution to journalArticle

46 Citations (Scopus)


This paper presents a simple method to measure the relative permittivity of glass-epoxy printed circuit boards (PCBs). In this method, relative permittivity as a function of frequency is measured using an actual PCB. In order to estimate relative permittivity, the reflection coefficient is measured with a network analyzer. Relative permittivity is calculated by observing the frequencies of the resonant cavity modes. We show that the relative permittivity of a FR-4 sample decreases from 4.3 to 4.2 at frequencies from 300 MHz to 2 GHz.

Original languageEnglish
Pages (from-to)515-519
Number of pages5
JournalIEEE Transactions on Electromagnetic Compatibility
Issue number4
Publication statusPublished - Nov 2001



  • Frequency characteristic
  • Mode identification
  • Permittivity measurement
  • Printed circuit board
  • Rectangular cavity resonator
  • Reflection coefficient

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Computer Networks and Communications

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