Wire radiation impact on system-level EMC

It is pointed out that a good understanding of the nature of electromagnetic fields emanating from a wire is necessary before the significance of wire radiation in system compatibility can be determined. The following points should be taken into account when considering wire radiation effects on system-level EMC. One should determine whether the induction term, the radiation term, or both are important for assessing the compatibility of the system; the common-mode current dominates radiation from a cable; the induction (1/r ²) term dominates the field for a typical MIL-STD-462 test below approximately 50 MHz-above that, the radiation (1/r) term dominates; the radiation (1/r) term dominates the field for typical FCC and CISPR tests; and the electrostatic (1/r³ ) term should be omitted unless there truly is a varying charge distribution along the line