A Slot Line Microwave Dielectric Permittivity Sensor for Measure and Control of Laminated Materials

Measuring dielectric permittivity is a common technique to characterize materials which, sometimes, allows also a nondestructive detection of interesting physical properties of objects and systems.A dielectric permittivity sensor for microwave frequency range is proposed, based on a slot line resonator loaded by the material under test which appears particularly suitedfor characterization of laminated type dielectric materials.The experimentally measured sensitivity resulted about 160 MlIzt unit of εr. Some results on the use of the sensor to detect air gaps inside dielectric materials are also reported.