Analysis of ferrite beads for RF isolation on straight wire conductors

Author

Saario, S.A. ; Thiel, D.V. ; O´Keefe, Steven G. ; Lu, Jun W.

Author_Institution

Sch. of Microelectron. Eng., Griffith Univ., Nathan, Qld., Australia

Volume

33

Issue

16

fYear

1997

fDate

7/31/1997 12:00:00 AM

Firstpage

1359

Lastpage

1360

Abstract

Ferrite beads used for the suppression of electromagnetic interference (EMI) were analysed using the finite difference time domain (FDTD) method. The presence of the bead results in reflected current, cable radiation and resonant characteristics which significantly affect the ability to suppress currents uniformly over a wide frequency range. A typical low conductivity ferrite bead (σ=1 μS/m, ε_r=1, μ_r=100), with length L=21 mm and outer diameter D=11 mm is shown to be a poor isolator at 1.03, 1.71, 2.37 and 2.93 GHz due to this resonance phenomenon. The effective suppression of EMI depends on the properties and dimensions of the ferrite bead in addition to the frequency of operation

Keywords

UHF devices; conductors (electric); ferrite devices; finite difference time-domain analysis; interference suppression; radiofrequency interference; 1.03 to 2.93 GHz; EMI suppression; FDTD method; RF isolation; cable radiation; electromagnetic interference; ferrite beads; finite difference time domain method; reflected current; resonant characteristics; straight wire conductors;

fLanguage

English

Journal_Title

Electronics Letters

Publisher

iet

ISSN

0013-5194

Type

jour

DOI

10.1049/el:19970934

Filename

612149