Extreme Ultra-Wideband Radar-Based Compact 3D Terahertz Imaging System

Terahertz technology is a promising solution in the field of nondestructive testing, imaging, and sensing. At this spectrum the radiation can penetrate a wide variety of non-conductive materials while remaining non-ionizing and safe for biological tissues.
In this work, transceiver units based on the FMCW radar concept operating in terahertz frequencies are integrated with optomechanical components to construct a compact mobile terahertz scanner for 3D imaging. To achieve a tunable and extremely broadband terahertz FMCW radar, photomixing phenomena is used for terahertz generation and detection. The high-resolution 3D imaging capabilities of the optoelectronic terahertz FMCW radar and its wide-reaching applications in various domains are investigated and validated here. Moreover, a novel application for material characterization is studied, namely the thickness measurement of electrode films of battery cells used in battery electric and hybrid vehicles (BEV and EHV). By incorporating an aspherical telecentric f-theta lens into the photonic FMCW radar system, this work focuses further on precise and consistent imaging performance across a scanning area with a large field of view.