Probe Characterization for Electromagnetic Near-Field Studies

Probes used for contactless electromagnetic field capture or injection are characterized. Depending on the probe structure, they interact preferentially with the electric or magnetic field. The optimal size of the probes for broad-frequency-band measurements is investigated. However, it is shown particularly for the magnetic field probe that considerations about the size and the structures presented in this paper are not sufficient for a good discrimination between electric and magnetic fields. Then, the space resolution of near-field measurements is discussed, with application to the field capture of a microstrip line under operation.