EM Topology for Interference Control

Interference control for large systems is complicated because of the physical and electrical complexity of the systems. This chapter discusses electromagnetic topology and its relation to interference control. It covers the various aspects involved in partitioning of systems by nested enclosures and topological concepts to preserve shielding integrity. The chapter introduces the concept of nested enclosures, and shows the proper techniques of passing grounds and other conductors through the shield. It also discusses the effects of apertures on shielding effectiveness and shows how shielding effectiveness can be degraded by fields diffusing through conductive surfaces. Apertures are usually required for access such as windows and doors, ventilation, and a host of other facility requirements. These apertures must be designed so that access is provided without compromising the electromagnetic compatibility of the system. The chapter includes a design example to calculate the voltage induced in a metallic loop placed on a spherical shield of different metals.