Analysis of noise coupling from printed circuit board to shielding enclosure

The power distribution network in a printed circuit board (PCB) inside a compact-size enclosure is an effective path for high-speed digital noise to be coupled to the RF receivers inside the same enclosure, causing RF interference (RFI) issues. This noise coupling mechanism from PCB to shielding enclosure is investigated in this paper using the cavity model and the segmentation technique. In this approach, the structure of an enclosure with a PCB inside is divided into cavities with both horizontal and vertical connections. Modeling result agrees well with full wave simulations, and the simulation time is considerably reduced. Furthermore, the relationship among the noise coupling, the PCB-related resonances, and the enclosure-related resonances is studied as well.