• Refined model predicts cavity resonance in shielding enclosures with accuracy. • Effective dielectric constant enhances theoretical cavity resonance prediction. • Near-field distribution reveals internal EMI risk in shielding cabinets. • Re-radiation tests confirm that shielding cabinets can emit unwanted EMI. • FEM simulations validate theoretical and measured resonance behavior. The achievement of optimized performance, miniaturization, and the development of new advanced functionalities in electronic devices has a significant impact on their electromagnetic compatibility (EMC). The use of a board-level shield (BLS) is an effective approach to minimize electromagnetic interference (EMI) and improve EMC in electronic devices. Shielding cabinets are commonly used in electronic systems to contain and reduce EMI. However, the increasing operating frequencies of modern electronic systems can cause cavity resonance in shielding cabinets, increasing EMI levels within specific frequency ranges and potentially causing interference. This study presents a refined analytical and numerical approach to accurately predict the resonant frequency of shielding cabinets mounted on printed circuit boards (PCBs). An effective dielectric constant formulation is introduced to account for the combined influence of air and the PCB substrate within the cavity, significantly improving the accuracy of theoretical predictions. The analytical model is validated using Finite Element Method (FEM) simulations and two complementary experimental setups: transmission loss measurements and re-radiation characterization. The results demonstrate excellent agreement between theory, simulation, and measurements, with resonance prediction errors below 0.18 GHz. The findings provide practical design guidelines for anticipating and mitigating cavity resonance effects during PCB and shielding cabinet development, ensuring that shielding solutions enhance rather than degrade EMC performance.
Martínez et al. (Sun,) studied this question.