Thin sample dielectric properties measurement using open-ended coaxial probes and FDTD calculations

Open-ended coaxial probes have been used for broadband dielectric properties measurements for several years. However open-ended probes have been limited to measuring "thick" samples, (e.g., samples that are thick enough to contain the majority of the electromagnetic field that is penetrating the sample). This is known as the infinite sample criteria. In conjunction with our ongoing research activities in the area of microwave processing of materials, we have developed a metallized ceramic coaxial probe for broadband, high-temperature dielectric properties measurements. We have also developed a method of using the metallized ceramic probe in conjunction with finite-difference time-domain (FDTD) numerical methods to make dielectric properties measurements on thin samples. The method is described and results are given to show the validity of the measurement procedure. Results from 2.5 mm thick Zirconia and 5 mm Teflon samples are accurate, and the developed measurement procedure is therefore promising. Results from error analysis calculations are also presented to help guide the successful implementation of the measurement procedure.