Electromagnetic Reverberation Chambers

Chapter 7

Measurement of the Shielding Effectiveness

7.1. Introduction

The measurement of shielding effectiveness was one of the first applications of reverberation chambers devoted to electromagnetic compatibility [DEG 07,HAT 88, LEF 06].

Usually, shielding effectiveness is expressed in terms of an attenuation brought by a shield inserted between the electromagnetic disturbance source and the dedicated protected circuit. In the context of the measurement methods highlighted in this chapter, the circuit will be constituted by a field probe or by the loads at the ends of a cable or of a connector. This context has thus led us to subdivide the analysis into three parts, depending on whether our focus is the shielding protection of cables or connectors, the shielding protection of enclosures hosting electronic circuits, or the characterization of the attenuation brought by various shieldingmaterials.

The next sections of this chapter will develop these different aspects of shielding measurements. After suggesting in section 7.2 several definitions of the shielding effectiveness, section 7.3 tackles the question of the measurement of the effectiveness of shielded cables and connectors in reverberation chambers. Knowing that we aim at disturbances coming from RF emissions, the cable shields behave like wiring circuits immersed in the ideal random field distribution of the reverberationchamber.

The physical analysis detailed in section 7.3 leads to the search for a methodology enabling ...