Characteristic admittance is the mathematical inverse of the characteristic impedance.
The general expression for the characteristic admittance of a transmission line is: where The current and voltage phasors on the line are related by the characteristic admittance as: where the superscripts
+
{\displaystyle +}
represent forward- and backward-traveling waves, respectively.
A
transmission line
is drawn as two black wires. At a distance
x
into the line, there is current
phasor
I(x)
traveling through each wire, and there is a
voltage difference
phasor
V(x)
between the wires (bottom voltage minus top voltage). If
is the
characteristic admittance
of the line, then
for a wave moving rightward, or
for a wave moving leftward.
