Military electronic equipment, high frequency, miniaturization, integration, functional, bringing more and more serious problem of electromagnetic compatibility. Currently, to control equipment electromagnetic interference, essentially all of the military electronic equipment are required to participate in GJB151A (military equipment and subsystems, and sensitivity to electromagnetic emission requirements) under the electromagnetic compatibility test. Current probe is used to extract the cable as the electromagnetic noise of the instrument, because no conductive contact with the source wire, the system does not work or normal random arrangement, often used GJB151A the CE101, CE107, CS114, CS115, CS116 and other military electromagnetic compatibility test program . Most of the domestic test for electromagnetic compatibility of current probes are from foreign countries, such as Yi Muke, SOLAR, FCC, AH SYSTEM others. In fact, the current probe is a broadband current transformer, which is a core part of the ring in half the high permeability core, the core has n turns on the winding coil, placed in a metal shell in the non-magnetic , tested the cable through the core probe, the core induces a voltage on the coil, through the BNC or N-type connector output to the spectrum analyzer, the structure shown in Figure (1) below. Typical current probe coil is generally 7 to 8 turns, to ensure that the maximum flat frequency band and the insertion impedance of less than 1Ω .