Measurement setup for non-destructive complex permittivity determination of solid materials using two coupled coaxial probes

A non-destructive microwave measurement setup for broadband complex permittivity determination of solid materials over a frequency band from 0.05 GHz to 6 GHz is presented. The setup design was optimized for measurements of glass materials with planar and convex surfaces, but works with other dielectric materials as well. The measurement method is based on the near field coupling of two open-ended coaxial probes through the material under test (MUT). A theoretical modeling of this measurement configuration was performed, using a 3D full-wave electromagnetic field simulator. Two identical coaxial probes and an equivalent calibration kit, in order to perform a TRL calibration of the proposed setup, were designed. The calibration procedure of the measurement setup is explained and experimental results are presented.