FDTD analysis of electromagnetic fields caused by sparks between charged metals

Fujiwara, Osamu; Kawaguchi, Kei

doi:10.1002/(sici)1520-6432(200002)83:2<44::aid-ecjb6>3.0.co;2-7

“…The diagram indicates that when image charges ±q n (n = 0, 1, 2, 3, …) are spaced at n (n = 0, 1, 2, 3, …) in Figure 5, electrostatic field at r ≫ 2a + can be found as a total field of all dipoles with length n (n = 0, 1, 2, 3, …). [9][10][11] That is, electrostatic field at r ≫ 2a + is -fold electric field of current dipoles during discharge of electric dipoles with point charges ±q spaced at . Dipole current i(t) corresponds to discharge current.…”

Section: Image Dipole and Transient Electric Fieldmentioning

confidence: 99%

Verification of Measurement Waveforms of Transient Electric Field caused by Micro-gap Spark using Optical Electric Field Probe

Taka

¹

,

Kawamata

²

,

Ishigami

³

et al. 2018

Self Cite

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With the widespread use of wearable terminals, machine to machine (M2M) and internet of things (IoT) equipment, electrostatic discharge (ESD: Electrostatic Discharge) due to electrification of humans and objects can cause electromagnetic interference (EMI) inside these devices, which is called intra-EMC (Electromagnetic compatibility). This type of the EMI issue would be often derived from a steep transient electric near field generated by less than 1 kV spark discharges between micro-gaps. To clarify the characteristics of such electric near field, therefore, an optical electric field probe, which does not disturb any electromagnetic fields to be measured, has been used to measure the transient electric field caused by a micro-gap spark when charged metal spheres collide, while it is not fully understood whether or not the probe output precisely responds to the transient electric field in the vicinity of the discharge point. In this study, the measured waveforms of the above-mentioned electric field are verified by comparison with the electrostatic field theoretically derived from image charges and the transient electric field calculated from an image dipole charge model combining a spark resistance law. The result reveals that at a distance near the discharge point the optical field probe does not properly work due to the presence of the electrostatic field, whereas the transient electric field at a distance away from more than twice the diameter of metal spheres from the discharge point can be correctly measured because of sufficient attenuation of the electrostatic field component. K E Y W O R D Selectrostatic discharge, micro-gap discharge, optical electric field probe, transient electric field, verification Electron Comm Jpn. 2019;102:3-11.

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“…As regards collision ESD field between spherical electrodes, according to References, 10,11 induced region can be assumed within the electrode's radius from spark point, and radiative region can be assumed at a distance exceeding the electrode's diameter; thus, transient magnetic field measured in the two regions are called here “magnetic near‐field” and “magnetic far‐field,” respectively.…”

Section: Resultsmentioning

confidence: 99%

“…In Equation (), the 1/ d term on the right side is dominant at d >> cτ , 12 but magnetic far‐field can be assumed if d >2 a 10,11 …”

Section: Validationmentioning

confidence: 99%

Waveform conversion and validation of transient magnetic field due to ESD using equivalent circuit of magnetic near‐field probe

Wang

¹

,

Kawamata

²

,

Ishigami

³

et al. 2022

Electrical Engineering Japan

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With a 6 GHz band high resolution magnetic near‐field probe (XF‐R 3‐1) produced by Langer, the transient magnetic fields due to collision ESDs (electrostatic discharges) between metal balls at a charging voltage of 600 V were measured near the spark point to investigate a dipole radiation mechanism. In this study, as an object of considering the measured magnetic field waveforms, two different equivalent circuits of the magnetic near‐field probe are derived based on the probe response waveform observed by a TDR (time domain reflectometer) with a 10 ps rise‐time pulse and the probe reflection coefficient measured with a 26 GHz network analyzer. Waveform conversion formulae from the probe output voltage to the magnetic field are given. The validity of the conversion methods is verified by comparing the measured conversion waveforms and their frequency spectra in addition to the converted spectra by the Langer field correction curve with the calculated waveforms of the transient magnetic far‐fields from a dipole model consisting of image charge pairs and the Rompe‐Weizel spark resistance formula. The probe conversion formulae presented here are valid within the frequency range of the 6 GHz probe band, however, beyond the band the resonance peaks at multiple frequencies over 8 GHz appear on the spectra, which causes damping oscillations peculiar to the probe with multiple frequencies to the time domain waveform.

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“…In this paper, we examine waveforms of transient electric fields caused by micro-gap spark discharge between charged metal spheres measured by an optical electric field probe in the previous study 5 ; specifically, we verify the measured waveforms through comparison with electrostatic field derived theoretically using electric dipoles, and transient field calculated using a dipole charge model combined with a spark resistance formula. [8][9][10][11][12]…”

Section: Introductionmentioning

confidence: 99%

Verification of measurement waveforms of transient electric field caused by micro‐gap spark using optical electric field probe

Taka

¹

,

Kawamata

²

,

Ishigami

³

et al. 2019

Elect Comm in Japan

Self Cite

1

0

View full text Add to dashboard Cite

With the widespread use of wearable terminals, machine to machine (M2M) and internet of things (IoT) equipment, electrostatic discharge (ESD: Electrostatic Discharge) due to electrification of humans and objects can cause electromagnetic interference (EMI) inside these devices, which is called intra-EMC (Electromagnetic compatibility). This type of the EMI issue would be often derived from a steep transient electric near field generated by less than 1 kV spark discharges between micro-gaps. To clarify the characteristics of such electric near field, therefore, an optical electric field probe, which does not disturb any electromagnetic fields to be measured, has been used to measure the transient electric field caused by a micro-gap spark when charged metal spheres collide, while it is not fully understood whether or not the probe output precisely responds to the transient electric field in the vicinity of the discharge point. In this study, the measured waveforms of the above-mentioned electric field are verified by comparison with the electrostatic field theoretically derived from image charges and the transient electric field calculated from an image dipole charge model combining a spark resistance law. The result reveals that at a distance near the discharge point the optical field probe does not properly work due to the presence of the electrostatic field, whereas the transient electric field at a distance away from more than twice the diameter of metal spheres from the discharge point can be correctly measured because of sufficient attenuation of the electrostatic field component. K E Y W O R D Selectrostatic discharge, micro-gap discharge, optical electric field probe, transient electric field, verification Electron Comm Jpn. 2019;102:3-11.

show abstract

FDTD analysis of electromagnetic fields caused by sparks between charged metals

Cited by 4 publications

References 4 publications

Verification of Measurement Waveforms of Transient Electric Field caused by Micro-gap Spark using Optical Electric Field Probe

Verification of Measurement Waveforms of Transient Electric Field caused by Micro-gap Spark using Optical Electric Field Probe

Waveform conversion and validation of transient magnetic field due to ESD using equivalent circuit of magnetic near‐field probe

Verification of measurement waveforms of transient electric field caused by micro‐gap spark using optical electric field probe

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