- Full text PDF available (4)
— Open-ended coaxial line probes (OCs) are systematically analyzed by means of numerical 3-D finite element calculations in combination with experimental investigations for microwave dielectric spectroscopy on fine grained soils. The probes, based on conventional coaxial lines and connectors (N, SMA), are broadband characterized in the frequency range from… (More)
Precise knowledge of the frequency dependent electromagnetic properties of porous media is urgently necessary for successful utilization of high frequency electromagnetic measurement techniques for near and subsurface sensing. Thus, there is a need of systematic investigations by means of dielectric spectroscopy of unsaturated and saturated soils under… (More)
This contribution presents a dielectric spectroscopy study in which four different devices in combination with five different probes were used in order to measure the complex effective relative permittivity of a fine-grained soil in a frequency range from 1 MHz to 40 GHz. Subsequently, the dielectric measurements were combined to obtain a permittivity curve… (More)
Spatial Time Domain Reflectometry (spatial TDR) is a measurement method for determining water content profiles along electrically insulated probes (transmission lines). The method is based on the inverse modeling of TDR reflectograms using an optimisation algorithm. By means of using flat ribbon cables as sensors it is possible to take two independent TDR… (More)
The paper addresses the following topics in relation to the grading curve: (i) the densest – loosest packing problem, (ii) pore characterisation and pore size distribution curve, (iii) the calculation of the unsaturated soil functions from the grain size or pore size distribution curve.
The frequency dependence of dielectric material properties of water saturated and unsaturated porous materials such as soil is not only disturbing in applications with high frequency electromagnetic (HF-EM) techniques but also contains valuable information of the material due to strong contributions by interactions between the aqueous pore solution and… (More)
A high-frequency electromagnetic measurement technique is employed to investigate dielectric properties of a fine-grained soil. As a case study, a standardized compacted fine-grained soil was investigated using a coaxial transmission line cell in combination with vector network analyzer technique in a frequency range from 1 MHz to 3 GHz. The measurement… (More)