Feasibility of conducting unit level EMI tests in a system level environment

The advantages of conducting MIL-STD-462 type tests for US Naval systems while the equipment was configured in a system level type of environment have been discussed by D.S. Dixon (1989). The authors evaluate the possibility of using a thin (1 mil) metallic enclosure to permit RE-02 electric field measurements to be conducted, over the 10 kHz to 10 GHz frequency range, on the individual equipment enclosed within the electrically thin portable shield enclosure. Initial evaluation of the electromagnetic (EM) performance of a very portable, 1 mil thick aluminized plastic enclosure, which is kept one foot away from a 24"×24"×72" electronics cabinet, indicates that the enclosure would have excessive EM interaction with the unit-under-test (UUT) for frequencies at the low end of RE-02 frequency range. Therefore, to ensure that the UUT\´s radiated EM fields are not being perturbed, the enclosure must be made larger to increase the separation between the enclosure and the UUT or the concept will have to be reversed so that the portable enclosure shields one or more other units to determine the sources of a piece of equipment\´s high level emissions