Comparison of different methods for dielectric properties measurements in liquid sample media

Abstract

Nondestructive techniques to measure dielectric properties of aqueous samples have become a crucial research topic for their impact on emerging biomedical applications. Accurate modeling of the dielectric behavior of biological tissues is fundamental to properly assess biomedical microwave imaging techniques. But it is also highly demanded to enable more reliable pretreatment planning for therapeutic technologies using electromagnetic fields such as hyperthermia and thermal ablation. This paper compares 2 well-documented measuring methods based on open-ended coaxial probe with a broadly commercialized set-up and existing literature. Measurements were carried out across the frequency range 0.5-4.5 GHz at 20°C on deionized water, methanol, and 2-propanol samples. This selection of media under test is justified by their stability and existing literature on them. Moreover, their permittivity values well cover the variability range in biological tissues. This comparative study shows that the Stuchly and Stuchly method calibrated using deionized water, methanol, and open circuit conditions is a valid alternative to the commercial set-ups available.