Novel Dielectric Spectroscopy Approach with the Open-Ended Coaxial Probe for Materials with Uneven Surface in Biomedical Applications

Since the turn of the century numerous studies have focused on characterizing the dielectric properties of biological tissues. Despite this progress, significant gaps persist in our understanding of certain tissue types, and data variability across different studies remains a concern. A widely adopted method for microwave characterization is the open-ended coaxial probe technique. This approach permits the use of different probe types, facilitating measurements across a broad frequency range. Nonetheless, a key drawback of this technique is that the size of the sensing volume changes with the probe diameter and it is often hard to achieve good contact between the investigated sample and the probe aperture. The aim of this work was to develop a new methodology for measuring properties of materials with irregular surfaces utilizing open probe technique. To this end, the samples are immersed in well-known background materials and their properties are then extracted from measured bulk properties.