A Novel Microwave Non Contact Current Probe with High Spatial Resolution

摘要

A high-resolution microwave non-contact current probe is described. Novel techniques are used in order to reduce the intrusive E-field pickup, which has restricted the performance and usefulness of such probes in the past. These include a probe structure that has built-in E-field screening and a high performance broadband differential amplifier. A rigorous testing procedure is described which asserts that the probe is truly responding almost entirely to the H-field. The probe operates up to 9GHz and has been used to profile the current distribution between the multiple cells of a power transistor at 3GHz, the first time such a direct measurement of this kind has been reported.