Transmission lines

Abstract

Y are functions of the voltage, the current, and the location on the transmission line. Ohm’s law of a transmission line, which is the amount of voltage drop on a transmission line per unit distance of voltage transmission is expressed as (9.1) dV dz IZ ˙ ˙ ˙ = −/()V m where · V is the transmission line voltage (Volt), · I is the transmission line current (Ampere), Z is the series impedance per unit length of the transmission line (Ω), and z is a one-dimensional coordinate placed in parallel to the transmission line (meter). The equation of current decrease per unit length is (9.2) where · Y is the shunt admittance per unit distance of the transmission line (S/m). Combining (9.1) and (9.2), the Telegrapher’s equation or Helmholtz’s wave equation for the trans- mission line voltage is [1-3].