Measurement of shielding effectiveness of electrically-small enclosures

In the following we propose a technique for determining the shielding effectiveness of an electrically small enclosure with an electrically small aperture. In particular, we use this technique to explore the shielding characteristics of rectangular boxes used to shield devices. Measurement and simulation results are presented in order to validate the technique and to show that, when a source is placed inside the box, different aperture shapes on the face of the enclosure will produce different internal and external field patterns, and have different shielding characteristics.