Microstrip is a form of transmission line consisting of a conductive trace over a ground plane separated by a dielectric material. The benefit of microstrip is that mounting components is greatly simplified since the conductor is exposed to the space above the dielectric material. The fact that the conductor is exposed also means that there is greater coupling with neighboring traces since the electric field lines must curve back downwards to the ground plane below the dielectric. Calculating the characteristic impedance of the microstrip line is slightly more complicated than for other types of transmission lines due to the fact that the electric fields are partially in air and partially in the dielectric material.