characteristic impedance (Zo)

The impedance of a circuit that, when connected to the output terminals of a uniform transmission line of arbitrary length, causes the line to appear infinitely long. Note 1: A uniform line terminated in its characteristic impedance will have no standing waves, no reflections from the end, and a constant ratio of voltage to current at a given frequency at every point on the line. Note 2: If the line is not uniform, the iterative impedance must be used. 2. For Maxwell's equations, the impedance of a linear, homogeneous, isotropic, dielectric propagation medium free of electric charge, given by the relation Z=(/ε)^½ where is the magnetic permeability and ε is the electric permittivity of the medium.