Electrical Characterization of Glycerin: Water Mixtures: Implications for Use as a Coupling Medium in Microwave Tomography
Journal article, 2017

We examine the broadband behavior of complex electrical properties of glycerin and water mixtures over the frequency range of 0.1-25.0 GHz, especially as they relate to using these liquids as coupling media for microwave tomographic imaging. Their combination is unique in that they are mutually miscible over the full range of concentrations, which allows them to be tailored to dielectric property matching for biological tissues. While the resultant mixture properties are partially driven by differences in the inherent low-frequency permittivity of each constituent, relaxation frequency shifts play a disproportionately larger role in increasing the permittivity dispersion while also dramatically increasing the effective conductivity over the frequency range of 1-3 GHz. For the full range of mixture ratios, the relaxation frequency shifts from 17.5 GHz for 0% glycerin to less than 0.1 GHz for 100% glycerin. Of particular interest is the fact that the conductivity stays above 1.0 S/m over the 1-3-GHz range for glycerin mixture ratios (70%-90% glycerin) we use for microwave breast tomography. The high level of attenuation is critical for suppressing unwanted multipath signals. This paper presents a full characterization of these liquids along with a discussion of their benefits and limitations in the context of microwave tomography.

microwave tomography

Bound water

relaxation frequency

coupling liquid



Paul M Meaney

Chalmers, Signals and Systems, Signalbehandling och medicinsk teknik, Biomedical Electromagnetics

Colleen J. Fox

Dartmouth-Hitchcock Medical Center

Shireen D. Geimer

Thayer School of Engineering at Dartmouth

Keith D. Paulsen

Thayer School of Engineering at Dartmouth

IEEE Transactions on Microwave Theory and Techniques

0018-9480 (ISSN)

Vol. 65 5 1471-1478

Subject Categories

Electrical Engineering, Electronic Engineering, Information Engineering





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