Traditional methods for establishing EMC and field density can be predicted using a field approximation routine based on well documented principles. In the process of reducing spurious emissions or interference EMC engineers will use suppression techniques of shields, boxes and cages. These methods have been found to work in normal applications but as the frequency expands traditional methods of EMC suppression may not be as effective. The far field approximation technique presented in this paper allows an engineer to test a sub assembly in the near field and then have a value which can be extrapolated to the far field. Measurements taken using the broadband near field "magnetic probe method" used with an automated scanning system (EM-ISight) can be extrapolated to either a 3m or 10m range space. Such a technique can allow the design engineer to determine the effectiveness of their design prior to the final integration of an assembly thus understanding better the uncertainties of a previously developed reference design or suppression methods.
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