Accurate measurement of complex permittivity of liquids using the in-waveguide technique

The complex permittivity of a number of liquids has been measured using the in-waveguide technique at the X and Ku band. A particular piece of waveguide is designed for the measurement of liquid materials. A TRL (thru-reflect-line) calibration technique is applied for the calibration of this waveguide system. The measured permittivity results of some liquids such as methanol and propyl alcohol compare well with those measured using an open-ended waveguide technique.