Effective shielding is more than a pretty facade

The least understood of many elements which the designer has to consider in connection with electromagnetic compatibility problems is, perhaps, related to shielding. Electromagnetic shields are metallic barriers used to contain or reduce the coupling of electromagnetic energy. Maxwell's equations for time-varying fields can be used for an analysis of the effectiveness of a shielding barrier. However, these equations can become quite complex even for simple models. For this reason, transmission line theory, applied to shielding applications, has been employed to determine total shielding effectiveness. The design of suitable shielding barriers is discussed. The material employed can consist of metal, including high-permeability materials, and plastics with a conductive medium. Attention is given to approaches for accessing the interior of the shielded space, the ideal shielding joint, a reusable sealing method, conductive gaskets, conductive elastomers, correct grounding, the shielding of cables, and the use of waveguides.