Permittivity measurement of low and high loss liquids in the frequency range of 8 to 40 GHz using waveguide transmission line technique

This paper presents the complex permittivity of a number of liquids measured using waveguide transmission‐line techniques. These liquids are measured over four frequency ranges: 8–12.4 GHz, 12.4–18 GHz, 18–26.5 GHz, and 26.5–40 GHz (or at the X, Ku, K, and Ka bands). The measured results of liquids are discussed and compared with results in the literature and the calculated data using Debye's method. Finally, statistical values such as the means and standard deviations, and the percentages of permittivity errors are computed for the consideration of data spread and error estimation. All of the possible sources of errors are also discussed with regard to improvements and developments of measurements in the near future.