Near magnetic field probe for detection of noise current flowing to uncertain directions

This paper proposes a new structure of the near magnetic field probe. In the case of detecting noise current on printed circuit boards (PCB) using conventional loop type probe, it is necessary to rotate directions of the probe because the probe has no sensitivity to the current perpendicular to the plane of the loop. Therefore, the new type probe with less directional dependence is required to reduce the measuring time for visualizing noise propagation path. We developed “butterfly type” probe which can detect the noise current flowing to uncertain directions. The probe consists of two triangle loops connected in one stroke drawing. Two kinds of evaluations (directional dependence, and position dependency against the microstrip line trace on a PCB) of the proposed probe were performed, and good characteristics were confirmed.