A simple technique for precision RF attenuation measurement

An accurate RF attenuation measurement, with small mismatch effect, is achieved without source and load being matched to the line impedance. Insertion loss measurements to the DUT and to the DUT fitted by quarter-wavelength lines are carried out, then the attenuation is obtained simply, unrelated to the source and load reflection coefficients. Experiment results on two 20-dB attenuators at 11 GHz show good agreements with those being impedance matched.