ESDガンの垂直結合板への間接放電で生ずる空間電磁界のばらつき

抄録

International Electrotechnical Commission (IEC) prescribes immunity tests (IEC61000-4-2) of electronic equipment against electrostatic discharge (ESDs), and specifies indirect discharges of an ESD-gun onto a vertical coupling plane (VCP) in the vicinity of equipment under test (EUT) for simulating personal discharges to conductive materials being adjacent to the EUT. According to IEC 61000-4-2 2001-04, the VCP shall be placed at a distance of 0.1m from the EUT, and the indirect discharges of an ESD-gun should be conducted to the centre of a vertical edge of the VCP, while the reference arrangement of EUT is not specifically determined. In the present study, by using a magnetic field probe and a half-wavelength dipole antenna in lieu of EUT, we measured their induced voltages due to electromagnetic fields spatially induced for indirect discharges of an ESD-gun onto a VCP, and investigated variations in peaks and waveform energies with respect to the measurement positions. As a result, we found that positions close to the ESD-gun provide variations by 1.46 (4.0) and 3.4 (27) times in peaks (waveform energies) of the induced voltages due to magnetic and electric fields, respectively, while positions away from the ESD-gun suppress their variations by 0.6 (0.4) and 0.2 (0.34) times, and discharges onto a vertical edge from the back side of a VCP could be expected to further reduce the above-mentioned variations.