Analysis and Modeling of the Complex Dielectric Constant of Bound Water with Application in Soil Microwave Remote Sensing

Abstract

Complex dielectric constant (CDC) of bound water determines the accuracy of the complex dielectric constant of wet soil. According to electrical double-layer structure and dielectric properties, the bound water on clay particle surface is divided into strongly bound water and weakly bound water. Based on this classification, models for the complex dielectric constants of bound water and soil are established taking into consideration factors such as temperature, moisture, texture, and microwave frequency. The results show that the fundamental reason why the complex dielectric constant of bound water is between that of ice and free water is the adsorption force which forms the electrical double-layer structure on the surface of clay particles. Low-concentration cationic solution could exist in free soil water and was found as the reason for the higher salinity and conductivity of free soil water, as compared to the measured soil solution. Results of soil CDC model are in good agreement with measured data across a wide range of microwave frequencies and soil temperature, moisture, and texture. The absolute root mean square error analysis also shows that the soil CDC model in this paper compared to the other models is more accurate.

Feasibility Study of an Industrial Moisture Content Sensor Based on Wheeler Cap

“…The material under this investigation is a mixture of paper and water. The losses due to a proportion of water in the paper can be modeled using similar techniques described in [10] [11] to obtain the complex dielectric constant (CDC) of the mixture. For accuracy, the model must be compared with the experimental data which are not available at this stage.…”

Enamel and Its Interaction with the Oral Environment

“…The Stern-Gouy electrical double-layer theory is used to describe the microscopic structure at the solid surface [32]. The outer enamel layer (less than 1 μm from the anatomical surface) is most likely a non-stoichiometric apatite.…”

An Enhanced Saline Soil Dielectric Constant Model Used for Remote Sensing Soil Moisture and Salinity Retrieval

“…For these saltwater-related parameters, many studies have already provided theoretical and empirical approaches for their calculation [37][38][39]. Specifically, the high-frequency extreme value of the dielectric constant of saltwater (ε sw∞ ) is regarded as having an identical value to the parameters of free water and is considered to have a specific value of 4.9 [44]. The Stogryn model gives semi-empirical formulas to acquire ε sw0 τ sw and σ sw [39].…”

“…Many studies have already demonstrated that salinity significantly influences the imaginary part of the saltwater dielectric constant [44,45]. However, the existing models have large errors when simulating this variable, especially for soil with high water and salinity contents [37].…”