Measurement of a Microwave Load Using One or Two Terminations of Known Reflection

A method is presented to determine the reflection coefficient of an unknown load by the use of a vector network analyzer (VNA), a known through connection, and only two (or even one) terminations of known high reflection, where load and terminations have to be connected to both VNA ports. This is possible for sexless coaxial connectors as well as for waveguides and on-wafer measurements. The new method is not restricted to low-reflective loads. The influence of deviations from the true reflection values of the high-reflective terminations on reflection measurements of low-reflective loads has been investigated where simple expressions for sensitivity coefficients are given. Experiments have been successfully carried out in the 7mm-PC-7 coaxial line system for frequencies from 2 to 18 GHz with known shorts and opens and with low- and medium-reflecting loads.