Flexible Implementation of Open-Ended Coaxial Probes for Dielectric Characterization of Biological Tissues

Open-ended coaxial probes are commonly used for characterizing the dielectric properties of biological tissues across the microwave frequency range. They uniquely enable broadband, non-destructive measurements, and can be used in-vivo. These dielectric probes are typically long, straight, rigid instruments. For some clinical in-vivo applications use of the probes in curved positions may be convenient to facilitate access to difficult to reach areas. In this work, we study the potential for performing measurements with probes flexed to different radii of curvature, and assess the accuracy in the resulting complex permittivity. We perform both electromagnetic simulations and experimental measurements, with a variety of curvatures and different tissue test materials. The results indicate that accurate dielectric properties can be achieved even when open-ended coaxial probes are curved to a high degree.