Design and accuracy analysis of a broadband six‐port reflectometer utilizing coupled‐line directional couplers

A design of a broadband six‐port reflectometer has been presented.Broad bandwidth has been achieved with the use of coupled‐line directional couplers. An appropriate modification of a standard six‐port which ensures uniform circle centers' distribution against frequency has been proposed. The influence of power detectors' uncertainty on the calibration procedure and measurement results is discussed, and the estimated measurement accuracy is given. The performance of the presented six‐port reflectometer has been experimentally verified by measurements of the reflection coefficient in a frequency range 2–3.5 GHz. The obtained results are in good agreement with measurements performed with a commercial vector network analyzer.