Interferometric Technique for High­ Sensitivity Measurement of Extreme Impedances

An all-electronic, I/Q-mixer-based interferometric technique to reduce measurement noise in the characterization of extreme impedances is presented. The proposed technique employs a standard vector network analyzer, an arbitrary waveform generator and an I/Q-mixer chain to generate a very stable cancellation signal. This hardware implementation enables frequency scalability, due to the large commercial availability of the mentioned components, and high stability, speed and repeatability, due to the fully electronic approach. The proposed technique is embedded in a scanning microwave microscopy (SMM) setup to demonstrate a more than 50% noise reduction in the measurement of dielectric materials. impedance measurement, dielectric measurement, microwave imaging.