A Microwave Impedance Meter Capable of High Accuracy (Correspondence)

Recent applications of directional couplers with auxiliary tuners for accurate VSWR and phase shift measurements have made possible a microwave impedance meter capable of high accuracy. It is similar to some bridges in that one obtains an initial detector null and a final null, before and after connecting the unknown. Both the magnitude and phase angle of the reflection coefficient of the unknown are determined in this operation, and these can be made direct reading if desired. The principle of operation is as follows.