Distance Characteristics of Field Peak Value of Transient Electric Field Caused by Sphere-Gap ESD Using a Optical E-Field Probe

Impulsive wideband electromagnetic noise is occurred by ESD (Electrostatic Discharge). The transient EM noise is an awkward problem that causes equipment malfunctions and failures. Therefore, in order to confirm the validity of the radiation model for discussing the mechanism of EM noise radiation by ESD, and the distance characteristic of the electric field peak value caused by ESD in a pair of spherical electrodes was examined using a wideband optical field probe. As a result, the field peak value was attenuated according to 1/d
³
of the distance d in the very vicinity of the discharge gap, and was attenuated according to 1/d
²
and 1/
$d$
at the far distance. From this result, it was confirmed that the EM field radiation caused by ESD of the pair of spherical electrodes can be explained by using the short dipole model.