Transmission line

Summary

A transmission line is a pair of conductors, such as a coaxial cable or two parallel wires. It carries electrical signals over distances comparable to or larger than the wavelength. On such a line, voltage and current travel as waves described by the telegrapher's equations. The line is characterized by its characteristic impedance and its propagation constant. Mismatches between the line and its load cause reflections, which matter in radio, high-speed digital circuits and power grids.