Research Information System
Journal of Optics (India), 2025 (ESCI)
Passive millimeter-wave (MMW) and TeraHertz (THz) imaging systems have gained popularity in recent years due to their cost-effectiveness and non-invasive nature when compared to active systems. This has led to a surge in research interest in this field. However, there has been a noticeable gap in the existing literature concerning characterization over variable target ranges. This article aims to address this gap by focusing on spatial resolution and other optical parameters in passive MMW/THz imaging systems, specifically for concealed object detection. The proposed solution introduces an optical design approach, which can be applied to various applications and purposes within the MMW/THz bands. This design approach is adaptable to different target ranges by manipulating the optical parameters within the limit of signal-to-noise ratio, thereby spatial resolution variations according to the specific target distances. After the design of the system, the MMW/THz detection and imaging system, the performance was tested, particularly concerning spatial resolution, depth of field (DOF) and false alarm rate parameters in the concept of detection. Additionally, the system’s imaging capabilities were evaluated under various conditions and environmental settings, spanning a range of target distances from 5 to 20 m. As a result, this research is expected to make a substantial contribution to the ongoing development of passive MMW/THz imaging systems, particularly in the context of concealed weapon detection at extended target ranges in the future.