Remote Material Characterization using mmWave FMCW Radar with Complex Baseband

Abstract

Material characterization has been a topic of interest for many years due to numerous applications in industry and research. Free space material characterization has seen lots of interest lately due to the non-invasive and non-destructive nature of the measurement procedure which is an important feature for some applications such as medical, food quality and production lines applications. In this thesis, a new method for characterizing materials and extracting parameters like dielectric constant, loss tangent and thickness, is presented. The method relies on using Frequency Modulated Continuous Wave (FMCW) radars with complex baseband to extract those features from both the magnitude and phase of the reflection coefficient of the material. Our study shows that utilizing both the magnitude and phase can enhance the accuracy of measurement and provide some extra information regarding the material configuration e.g., dielectric suspended in air or placed on a metal substrate. Using FMCW radar in free-space material characterization is a very good alternative to traditional free-space methods which rely on expensive and bulky VNAs. Two dielectric materials were tested, and the results were compared to data from literature.