Three probe reflectometer algorithm for complex coefficient measurements of water quality at microwave frequencies

The complex reflection coefficient (magnitude and phase) are measured using a three probe reflectometer algorithm. The measurement system consists of a Gunn diode source, 1 kHz modulator, attenuator, slotted line, A/D converter and a computer. A slotted line is used to measure three standing wave voltages corresponding to three probe positions which are one-eighth wavelength apart. Complex reflection coefficient results are reported for two standard liquids, namely, water and methyl alcohol. This measurement system can be used for water quality measurements.