Analysis and Treatment of U-Shape PCB I/O Ports to Reduce the EMI From Image-Plane Noise

摘要

This paper examines the electromagnetic interference (EMI) due to the existence of U-shape I/O ports used for connection with RJ-45 connectors. These ports result in noise when image planes are used. The investigation also provides a useful approach to potentially reduce this noise source. U-shape I/O ports are a popular printed circuit board (PCB) structure and exist on PCBs used for information technology equipment, where image planes are generally referred to conducting layers in the vicinity of the electric circuits and signal sources such as a power plane, ground plane, and chassis plane. Both numerical simulations and measurements are employed in the examination, and they exhibit useful characteristics to detect and reduce the influence of EMI on PCBs.