The microwave impedance measurement is an essential requirement for evaluating and improving the matching properties of microwave components and sub-systems. At microwave frequencies, S-parameters are most appropriate representation of microwave impedance.
The impedance of a precision co-axial air line can be calculated in terms of its dimensions and conductivity of material used that’s whys it is considered as a primary standard of impedance above 2 GHz. Uncertainties involved in such a calculation increase rapidly with the number of different materials involved in the construction and the complexity of the electromagnetic fields.
For coaxial transfer standards coupled sliding load technique (2 -18 GHz) and for wave guide system tuned reflectometer technique (5.8-18 GHz) have been established. Reflection coefficient / VSWR of the one port/ two port commercially available transfer standards are measured.
Broadband S-parameter measurements on one/two port artefacts in Type-N, APC-7 connector upto 18GHz
Primary and transfer waveguide standards (Ku band)
S- Parameters measurements are performed using a vector network analyzer (VNA). For These measurements the VNA must first be calibrated. Below two 2 GHz VNA is calibrated using Short-Open-Load (SOL) technique and using LRL above 2 GHz.
In view of the wide range of Reflection coefficient / VSWR and frequency band customers are requested to consult CFCT, NPL on the cost and details of the measurements or calibrations required.