structure of conductive and insulating layers. A basic printed circuit consists of a flat sheet of insulating material FR4, Rogers or Polyamide for flexible circuits, and a layer of copper foil, laminated to the substrate. Chemical etching divides the copper into separate conductive lines called stencil tracks or circuit paths, pads for connections, metallized
the better adaptation is required. When producing the printed circuit with stencil controlled impedance, the impedance will be controlled by acting on the dimensions of the tracks and the distance between them, i.e. the insulation. For a multilayer printed circuit with a specific stack-up, it must be taken into account that
copper), double-sided (two layers of copper on both sides of an insulating board), or stencil multi-layered (outer and inner layers of copper alternating with insulating layers). Among the multi-layer PCBs, the most common are the four-layer ones. The four-layer board has many more routing options in the internal layers compared