Self-Adjustable Microwave Homodyne Circuit for On-Line Simultaneous Attenuation and Phase Measurements

A chopped subcarrier method and a self-adjustable microwave homodyne circuit for simultaneous on-line attenuation and phase measurement under industrial conditions is presented. Substantial independence of measurement results on such metrological parameters of the circuit components as: microwave power level, frequency and detection efficiency has been achieved, without any control of microwave circuit parameters or enivironmental conditions. The independence between attenuation and phase measurements has been assured as well. Industrial applications of presented circuit for on-line moisture control of processed materials independent on material density or its layer thickness have been pointed out.