Comparison of power ratio and vector network analyzer techniques for measuring attenuation

By using a power ratio technique, we have lowered our uncertainty for attenuation measurements by a factor of about 4 (typical) when compared to our vector network analyzer uncertainty analysis. The power ratio technique is applicable to insertable 2-port devices with low reflection coefficients such as airlines and attenuators. The method is illustrated with 3 coaxial devices over a frequency range of 2-18 GHz and 2 rectangular waveguide devices over a frequency range of 50-75 GHz. Our results suggest that a significantly lower attenuation uncertainty could be justified by a re-analysis of the vector network analyzer measurements.