Measurement of Soil Moisture Content at Microwave Frequencies

Abstract

This paper discusses the measurement of moisture content present in soil by computing the dielectric constant of soil samples at three frequencies, using microwave free-space transmission technique. This leads to the determination of inherent moisture content in the samples by applying Topp's Equation. The change in the value of dielectric constant and the subsequent increase in the moisture content for each of the soil samples with added moisture levels at 20%, 23.1% and 28.6% are noted. Dielectric constant of some common materials such as free-space, FR4, acrylic and water are measured to check the efficacy of the proposed method.