Design of Signal Processors for Automatic Microwave Impedance Measuring Schemes Using Fixed Multiple Probes

As derived in a previous paper (IEEE-MTT, Dec. 1980, 1422-28), if three fixed, equi-distance, non-resonating probes are placed on a lossless waveguide terminated by an unknown impedance, then the real and the imaginary components of the unknown reflection coefficient seen under the central probe can be expressed by two equations based on the square-law outputs of the three probes normalized with respect to the incident power. In this paper, the author will report the signal processing schemes he is using to implement the equations.