Non destructive complex permittivity determination of glass material with planar and convex surface

A nondestructive microwave measurement setup for complex permittivity determination of glass material with planar and convex surfaces over a frequency range of 75 MHz to 6 GHz is presented. The measurement method is based on an open-ended coaxial probe technique. Two coaxial probes were constructed and their design was optimized in order to meet two contradictory requirements. On the one hand a large probe aperture is needed for sufficient measurement sensitivity at desired frequency range, on the other hand a small probe aperture is better suited for contacting non planar surfaces and avoiding air gaps. The calibration procedure of the measurement setup is explained and experimental results for planar and curved glass material are presented.