New Transmission Line Setup and Improved TDR Dielectric Spectroscopy Based on Reflection-Decoupled Ratio Method

Complex dielectric spectrum sums up the electrical properties that can infer a material’s composition. Among various dielectric spectroscopy methods, time-domain reflectometry (TDR) is an economical and efficient approach. A major recent development is a method known as the reflection-decoupled ratio (RDR) analysis, which is a self-referencing TDR dielectric spectroscopy using one-shot measurement independent of source variation and instrument mismatches. However, the current experimental system is yet to be practical. This study proposed using two coaxial cables to comprise the required mismatched transmission line system to allow the RDR method executed in a convenient and flexible manner. The tolerance level of connector mismatches was investigated to provide practical design guidance. Furthermore, we defined more rigorous measures of measurement sensitivity and information content for optimization of experimental design and calibration. Finally, the measurement accuracy and stability are significantly improved through a proposed inversion regularization, which increases data redundancy and reduces inversion nonlinearity.