Multiresolution analysis of electrostatic discharge current from electromagnetic interference aspects

This paper reports an analysis of the electromagnetic interference (EMI) aspects of electrostatic discharge (ESD) resulting from high-speed moving discharge phenomena. An orthogonal wavelet transform, which enables multiresolution decomposition of time-domain waves, was used to analyze measured ESD currents. The results showed that the high-speed moving discharges can increase the maximum amplitude and power of ESD currents, and that high-frequency components in particular tend to be affected by the movements of discharge electrodes. In the case of high-frequency components of ESD currents generated by charging voltages of 2, 5, and 15 kV, it was observed that the maximum amplitude was increased by 1.40 to 3.43 times, and the energy, defined by the sum of signals squared, was increased by 2.15 to 12.1 times compared to the results for the low-speed discharges. Chaos attractors reconstructed from measured ESD currents also showed that high-speed moving discharges decrease the stability of ESD current waveforms. From these results, it is apparent that EMI power generated by ESD tends to increase in the case of high-speed moving discharges.