Highlighting the distribution path of transient disturbances by near field scanning techniques

Many different measurement techniques are currently available to characterize the electromagnetic compatibility of electronic devices and systems. One of these techniques is known as the so-called “Surface Scan Method”. It is based on a near-field scanning technique and enables the visualization of the distribution of magnetic near field being present at the surface of printed circuit boards (PCBs). This technique provides an efficient way to find the sources of electromagnetic emission problems, as it can be used to pinpoint areas on the PCB which are usually the sources of the electromagnetic emission. In this paper it will be shown how such a surface scan technique can additionally be used to visualize the distribution path of transient disturbance currents. Such current surges can be caused by touching the PCB and thereby causing an electrostatic discharge directly into e.g. the connectors of the PCB.