Microwave Surface Reflection Method for Soil Moisture Determination Using frequency of 1.7-2.6 GHz

Abstract

Soil moisture is one of the critical components to be investigated in civil, geological and agricultural works. This is because the parameter can affect the physical and electromagnetic characteristics of soil, such as density and permittivity and this can further restricts soil application. Unfortunately, finding a suitable non-destructive model for accurate soil moisture determination is challenging. In this article, the concept and development of soil moisture determination via ground penetrating radar (GPR) principle and surface reflection method is explained. The system is designed to be used with standard horn antenna with a frequency of 1.7-2.6 GHz along with vector network analyzer (VNA). The proposed system can measure soil moisture of three types of soil samples such as sand, loamy, and clay with high degree of accuracy. In this research, microwave surface reflection method is applied to analyze the effect of soil moisture with its electrical properties using our novel GPR principle. The result of the research is promising with high percentage of agreement with Topp theoretical value. The values are 31% to 61% for sand, 5% to 42% for clay, and 44% to 54% for loamy. For validation on the system, a new type of soil is used for measurement, and the result has an accuracy of 93%. By using the proposed developed models, soil moisture estimation can be easily determined with minimal data input through a novelty GPR surface reflection method.