A proposed new definition and measurement of the shielding effect of equipment enclosures

This paper describes the rationale behind a new proposed measurement of the screening effect of an equipment enclosure that takes into account the contents of the enclosure. The method uses a set of representative contents for enclosures. The representative contents are equipped with surface field probes to measure the power entering the contents. The ratio of this power to the incident power density is used to derive a quantity with the dimensions of area, termed here the shielding aperture. The measurement technique is described and examples of measurements are given along with computed comparisons with the conventional shielding effectiveness of the enclosures used.