Characterization of radiometer using eight-term linear model

A novel eight-term linear model, allowing for general characterization of total power radiometer and for error-corrected noise temperature measurement, is introduced. It describes the dependence of the effective noise temperature of the noise source measured upon input mismatch affecting gain and noise of the radiometer. A technique for radiometer characterization based on the model and a constrained least-squares optimization are presented. Experimental results verifying this approach are shown. The technique is expected to be useful for broadband calibration of mismatched noise sources as well as for on-wafer noise characterization of MMIC´s