An interpolation scheme for precision intermediate frequency reflection coefficient measurement

The theoretical basis and the practical implementation of an objective approach to voltage reflection coefficient (VRC) interpolation in the development of radio frequency coaxial impedance standards are presented. Variants of the scheme apply to three impedances commonly used to calibrate vector reflectometers and vector network analyzers. The scheme permits impedance standards to be characterized in the intermediate frequency (IF) range (where, broadly speaking, IF refers to the frequency range 10 kHz to 100 MHz) in terms of their VRC values and associated measurement uncertainties. The scheme allows the use of commercially available devices (rather than specially constructed calculable devices) as impedance standards with VRC values traceable to national measurement standards. Measurement results are presented which illustrate the capabilities of the scheme.