We typically used in the PCB transmission line is embedded or attached one or more reference planes of conductive traces formed on the insulating material, the conductive material is copper traces Usually, the use of a dielectric called "FR4 "glass fibers.
Digital System Design The two most common structure is a microstrip transmission line and stripline. Microstrip lines are divided into standard and embedded microstrip line microstrip line. The former refers to the outer layer PCB traces, which is directly attached to the plane of the medium and exposed to air. The latter is improved, the difference is that the dielectric material covering the copper. Stripline transmission line in the two conductive planar structure surrounded by a dielectric material, it is the distance between the two electrically conductive planes is equal to the stripline can be divided into symmetric and asymmetric stripline.
Microstrip line is partially shown, which is composed of a dielectric substrate with a side of the central conductor, the other side of the ground plate structure, the substrate having a thickness of nine, the center conductor width is W. One made using lithography. This transmission line is simple in structure, easy processing, the microstrip circuit is easy to achieve miniaturization and integration, it is widely used in the PCB. 
Figure microstrip line
