A wideband line-line dielectrometric method for liquids, soils, and planarsubstrates

A line-line (LL) method for measuring the permittivity of materials up to m illimeter waves is proposed. It is based on a property of the well-known li ne-return-line (LRL) calibration technique developed for microwave circuits : the complex propagation constant of the two-line calibration standards ca n be extracted from the raw measurement of these two lines. Using this feat ure for a dielectrometric purpose, we combine this LL formulation with accu rate models for the propagation constant to extract from the measured value the permittivity of the medium surrounding, or contained in, the LL calibr ation lines. Choosing the line topology (planar, coaxial, or waveguide) acc ording to the nature and consistency of the material under consideration yi elds the permittivity of a wide variety of materials. In this paper, we dem onstrate the efficiency of the method for three kinds of substances: organi c liquids, soils, and planar dielectric substrates used for microwave plana r circuits. Advantages particular to each application are detailed in the p aper.