Design rules for an experimental setup using an open-ended coaxial probe based on theoretical modelling

In order to obtain a number of design rules for a setup involving an open-ended coaxial sensor to measure the dielectric constant of a material, several parameters are investigated. Using the recently developed spectral-domain model a clear view is given of the influence of the thickness of the test sample. Furthermore, a near-field study of the probe shows that reflections can occur at the transverse boundaries if the test sample is very small. The FDTD is used to investigate the minimum sample size required to simulate a medium that is infinite in the transverse direction. Finally, the influence of the flange of the probe is studied in order to determine the dimensions of the flange needed to correctly use the spectral-domain model.>