Authors: Rajendra S. Dhake, Vinod S. Khairnar, Rajkumar D. Rajkuvar, Sanika Hingalkar
Abstract: The dielectric response of soils is influenced by multiple factors including electromagnetic frequency, volumetric moisture content, soil composition, internal geometry of components and electrochemical interactions. These effects were characterized using the infinite sample technique to determine the real (ε/) and imaginary (ε//) parameters of the complex permittivity (ε*) of soils with different moisture contents. Measurements were conducted using an X-band microwave test bench operating at 9.44 GHz in the TE10 mode with a crystal detector and a slotted section. This configuration enables precise determination of dielectric parameters for bulk soil specimens. The observed behavior of ε/ and ε// shows an initially modest rise with increasing moisture followed by a pronounced increase at higher water contents, reflecting the strong influence of water on dielectric properties at microwave frequencies. Derived quantities such as a.c. electrical conductivity and dielectric relaxation times were also extracted from the permittivity data. The results demonstrate significant alterations in the electrical properties between dry and moist soils, with notable dependence on soil texture. These observations aid in interpreting ground-penetrating radar signatures and in the calibration of both active and passive microwave remote sensing systems.
DOI: http://doi.org/10.5281/zenodo.20825704
