Z0
Z0 is a term most commonly used in transmission-line theory and RF engineering to denote the characteristic impedance of a transmission line. It is the impedance that, when a line is terminated with the same impedance, yields no reflections along the line. Z0 is determined by the line's per-unit-length inductance and capacitance (L' and C'), and in real lines also by the series resistance per length and shunt conductance per length (R' and G').
For an ideal lossless line (R' = 0, G' = 0), Z0 = sqrt(L'/C'). In practical lines, Z0 is
The impedance matching condition ZL = Z0 minimizes reflections, and the quality of the match is described
Typical values: 50 ohms is standard for many RF systems, balancing power handling and loss; 75 ohms
Other uses of the symbol Z0 exist in different fields, but in engineering and physics literature, Z0