Magnetic field shielding effectiveness of a high-permeability shield on twisted pair and coaxial cables

The purpose of this study was to replace the existing electrostatic shields of select Mil-C-17 and Mil-C-915 shipboard cables with a high-permeability, electrostatic combination braided shield, of approximately the same thickness as the current electrostatic shield, and provide comparable shielding effectiveness of magnetic fields to the high-permeability, flexible shielding conduit. If comparable, this technique would facilitate effective shielding without the addition of the high-permeability, shielding conduit, therefore reducing shipboard cableway volumes. Tests have shown that the high-permeability braided shield material provides a minimum 12-dB magnetic field shielding effectiveness essentially constant across the frequency range of 70 Hz to 100 kHz. The use of these shields will reduce the magnetic fields radiating from and to adjacent shipboard cables and may provide enough shielding to eliminate the requirement for conduit