Frequency dependence of 50-Ω coaxial open-circuit reflection standard

The effective position of the open circuit in precision 7-mm 50-Ω coaxial transmission line is found experimentally to be located beyond the physical end of the center conductor by a distance 1.198+2.69×10^-10f² millimeters at f megahertz (<;18000). Because this determination is substantially identical to published theoretical values, the open circuit is recommended as a calibration standard for network analyzers.