Internal Defects Detection in Dielectric Multilayer Structures Using THz Based Technique

The use of dielectric multilayer has become a notable trend in various industries and fields. These stacked layers of dielectric materials offer a range of benefits, including improved electrical insulation and enhanced performance in varied environmental conditions like moisture. However, a major challenge lies in detecting internal failures, given that dielectric materials are often opaque, making visual inspection impossible to the naked eye. In response to this issue, interest has turned to the development of innovative diagnostic method to address this challenge. This is the main purpose of the work presented in this study. In this work, we have developed a diagnostic approach based on exploiting the properties of terahertz (THz) waves. This method aims to detect THz waves that reflect off interfaces present in the studied multilayer structure. Lastly, to confirm the validity of our theoretical approach, we designed and implemented an experimental test bench, enabling concrete measurements and empirically validating the conclusions drawn from the theoretical study. The experimental study, led on dielectric multilayer structure, validated established theoretical concepts, yielding results in line with expectations. The development of a diagnostic method, enabling the analysis of the health status of a multilayer dielectric structure, provides reassurance to stakeholders regarding internal degradation. Additionally, given the current focus on terahertz research and the lack of databases on dielectric electrical characteristics within this frequency range, this work opens the door to exploring and establishing such databases, facilitating the widespread adoption of this method across various fields and applications.