Broadband Soil Permittivity Measurements Using a Novel De-Embedding Line–Line Method

Abstract

A new de-embedding line–line method has been proposed for accurate complex relative permittivity ( $\varepsilon _{r}$ ) determination of soil samples loaded into an EIA 1-5/8” coaxial transmission line measurement system. The method has three main features. First, it bypasses the requirement of calibration of this system by using only two identical coaxial lines with different lengths. Second, it does not need any numerical technique for $\varepsilon _{r}$ determination. Third, it does not require knowledge of electromagnetic properties and thickness information of the bead used for supporting soil samples. The method is next validated by simulations performed using a full 3-D electromagnetic simulation program (CST Microwave Studio) and by $\varepsilon _{r}$ measurement of a polyethylene (PE) material. Finally, $\varepsilon _{r}$ values of three air-dried and water-saturated soil samples having 90% or more sand content with different electrical conductivities (ECs) and gathered from different areas of the city Gaziantep in Turkey, were measured.