An annular ring refers to the area of copper that surrounds the drilled hole (via) in a PCB. In multi-layer PCBs, vias are essential for connecting various layers. The annular ring ensures strong electrical conductivity between these layers, as it provides the necessary copper coverage around the hole.
When designing high-speed PCBs, understanding the core concepts is crucial for ensuring efficiency and functionality. This guide introduces key elements such as layers, vias, pads, and more to help beginners and professionals alike.