Enclosure shielding assessment using surrogate contents fabricated from radio absorbing material

The electromagnetic environment inside an equipment enclosure at high frequencies is strongly dependent on the absorption of energy by the contents. This effect is neglected by current shielding measurement standards. Here we extended the concept of shielding measurements using surrogate "representative contents" proposed at lower frequencies into the regime were the enclosure is electrically large. We demonstrate how a surrogate fabricated from radio absorbing material can be made to give the same overall absorption as a real printed circuit board and hence produce the same internal environment inside an enclosure during a shielding measurement.