Principal Investigator: Dr. Volkmar Schmidt
Research Associate: Frances Heinrich
Funding: Deutsche Forschungsgemeinschaft (DFG)
Period: 01/09/2014-31/12/2017
Objectives:
The permittivity is a physical property, which governs the propagation of electromagnetic fields. It is especially important for the propagation of radar waves, which have frequencies in the MHz-range. Radar waves are also used to image the subsurface, then the method is called ground penetrating radar (GPR). Whenever the GPR method is used to explore the subsurface, it is important to know the permittivity of the material. The permittivity can be measured in the laboratory, but data from small samples are often not transferable to natural rocks.
We have constructed a cylindrical measurement cell, which allows for the investigation of large rock samples. In combination with a vector network analyzer, the measurement system allows for rapid determination of spectral permittivity between 1 MHz and 500 MHz. For drill cores, spatial variations in permittivity can be resolved on a sub-centimeter scale.
Literature: SCHMIDT, V., WILTING, W., GRUSE, M., WAGNER, N., 2015: A cylindrical guarded capacitor for spectral permittivity measurements of hard rock samples in the MHz-range. Measurement Science and Technology 26:10, 105902.
