Mutual Influence of Cavity Resonances of a Shielding Enclosure on the Resonance of a Dipole inside that Enclosure

In recent years, a risk-based approach has been proposed to better manage EM-related risks of electronic systems. Within this approach it is critical to detect potential risks as much and as early as possible. Unfortunately, many hazards (potential contributors to risks) are “hiding” deep in the system and/or can only appear when “excited” under certain conditions. One such example is electromagnetic (EM) resonance of components and structures (e.g., traces, heatsinks, PCBs, enclosures) within electronic systems. These resonances can further lead to unintended and increased coupling effects which may result in seriously hazardous situations. In this paper, we consider the relatively simple but basic case of a trace (modelled as a dipole) within a closed metallic enclosure. Both quantitative calculations and full-wave EM-simulation results reveal the complexity of the possible resonance mechanisms and interactions.