ECM basis of systems

Dealing with the EMC (electromagnetic compatibility) of a system must be approached methodically, given the complexity of acquiring a justification that covers the expected performance requirements. The main difficulties relate to the coexistence of electrical and electronic equipment of different natures that may make up the system, as well as the cables that connect them. On this point, layout constraints can impose proximity favorable to crosstalk, which must then be managed by adapting protection. Added to this are the constraints of the external electromagnetic environment, which means that electrical chains must also be robust to such aggressions.

Other aspects include the size of the system, which introduces line loss effects not found at equipment scale, and resonance phenomena related to long wiring lengths. As we shall see in this article, the materials (metallic, composite) that make up the system are also involved in the EMC approach, since they contribute to the circulation of currents, depending on their intrinsic characteristics and the quality of the metallization. In addition, grounding and bonding are an integral part of the rules to be considered in the design phase, as they can have varying degrees of impact on the EMC specification levels for the equipment making up the system. All these points are discussed and illustrated in this article, using examples from the space launcher sector.

A glossary and table of acronyms are provided at the end of the article.