ADMITTANCE MODELS FOR OPEN-ENDED COAXIAL PROBES AND THEIR PLACE IN DIELECTRIC-SPECTROSCOPY

Starting from a rigorous formulation for the admittance of an open end ed coaxial probe, this paper identifies the simplifying assumptions th at are introduced to obtain more practical solutions. The predictions of the models are compared to each other and to experimental data obta ined on an independently calibrated experimental set-up. The advantage s and limitations of a model are determined by the theoretical derivat ion and the numerical solution. The model identified as most suitable for the measurement of the dielectric properties of biological materia ls is used to determine the relative permittivity and conductivity of muscle and skull bone in the frequency range 1 MHz to 20 GHz.