Directivity and polarization of electromagnetic radiation in low voltage ESD using spherical electrode

Directivity of electromagnetic field radiation in low voltage ESD (Electrostatic discharge) using a pair of spherical electrode was examined in experimental study. In addition to that, polarization effect of electromagnetic field radiation in a pair of spherical electrode investigates for clarify the radiation factors due to low voltage discharge below 1 kV. The experimental system consists of a pair of spherical electrodes, a horn antenna and wideband digitizing oscilloscopes. The ratio of directivity between front value and side value is about 18 dB in received voltage. Polarization of received voltage is clearly seen in electromagnetic radiation from a pair of spherical electrode. As a result, the EM field radiation looks like radiation from dipole antenna structure which makes the spark part of spherical electrodes a feeding point on the straight line passing through the tow sphere centers.