Noncontact Wideband Current Probes with High Sensitivity and Spatial Resolution for Noise Location on PCB

This paper develops an improved noncontact current probe for locating the noise source to estimate the electromagnetic interference emission on printed circuit board (PCB). The miniature current probe is fabricated in a four-layer PCB with high-performance dielectric RO4003C. The designs of isolated via array and matching via-pad structures are used to optimize the performance of probe. The probe can then be used for wideband electromagnetic compatibility test from 9 kHz to 10 GHz under narrow and complex conditions. The current probe can be sensitive enough to detect the weak current signal as small as -130 dBA and has a spatial resolution of 1 mm. The application of current probe in noise location on PCBs based on measured surface scan method is investigated in this paper. And two near-field measurement results compared with the reference probe are used to illustrate the new features of the probe.