Investigation of emission reduction effect from interface cables using amorphous magnetic-alloy film

This paper describes the effect of amorphous magnetic-alloy film in achieving emission reduction. This film is expected to replace ferrite because of a high permeability that exceeds Snoek´s limit and a low required thickness. In the investigation, an amorphous magnetic-alloy film was wound around a cable. Then, the cable´s emission levels were measured in a semi-anechoic chamber at a distance of 3 m. We examined to what degree film length, film position, and film thickness have an effect on the emission reduction from cables protected with amorphous magnetic-alloy films. The experiment results indicated that a 1 m long region wound with the magnetic-alloy film was required in order to achieve identical emission reduction levels as those of typical ferrite cores. In addition, the results show that the reduction effect was enhanced when a ferrite core was used in combination with the film, and that there were few advantages in reducing emission when a metallic thin film was applied on one surface of the magnetic-alloy film.