Testing non-linearity and saturation of a RF current probe

The behavior of RF current probes in simulated real usage conditions is considered, for what regards non-linearity and saturation in presence of large mains current intensity. A setup is described that allows the testing of variable bias conditions with RF probes in nominal zero air-gap and increased air-gap configurations (by interposition of Kapton layers). The tested units show an unaltered frequency response with additional 200-300 μm air-gap under DC bias currents of 100 A. Distortion by-products are measured after cleaning the signal generator with a high-order low-pass filter and found negligible and at the limit of the used instrumentation.