The research of current injection probe based on electromagnetic model

The precise modeling of permeability is the key to 3-D simulation of current injection probe. In this paper, using the short-circuit coaxial cavity to measure magnetic permeability, two equivalent models is carried out, that one of them is single-turn coil model, the magnetic permeability is calculated by integrating inductance, the other is transmission line-lumped parameter mixed model, the permeability is calculated according to the characteristics of transmission line. First-order Debye model can fit the complex permeability spectrum of ferrite, so this paper sets Debye model reasonably in corresponding parameters by comparison of the calculated magnetic spectrum. Core permeability and coil loops are two of the most important factors that affect the performance of current injection probe. After establishing a precise model, this paper focuses on researching the characteristics of these two factors on probe, which provides theoretical support for producing probes with smooth flatness and small insertion loss in wideband.