Conductivity limitations in single-reflection time-domain reflectometry

Numerical modelling of single-reflection time-domain reflectometry (TDR) is presented to demonstrate the limitations imposed by finite conductivity values upon recovering dielectric permittivity from the TDR reflected waveform. The results show conductivity to cause false dispersions resulting from the incomplete decay of the TDR waveform. The results are applicable to polar liquids and wet soils and suggest that conductivity should be less than about 0.01 S m -1 when relaxation frequencies exist above about 1 GHz.