A Compact Sub-THz Horn-Based Imaging System with Potential Application to Non-invasive Contactless Skin Cancer Detection

Terahertz waves have attracted increasing interest in the research community for skin cancer diagnosis owing to their sensitivity to water molecules, typically more abundant in tumors than in healthy tissues, and their non-invasive nature. In this work, a compact, contactless continuous-wave system employing a diagonal horn antenna is introduced and experimentally assessed in the 500-750 GHz band. The system capabilities are experimentally quantified using dedicated phantoms that reproduce the dielectric contrast between basal cell carcinoma and healthy skin. To this end, a methodology for dielectric characterization in the 500-750 GHz band and the fabrication of solid, easily reproducible phantoms is presented, integrating experimental and numerical data via dedicated look-up tables. The obtained experimental results, supported by detectability and measurement uncertainty analyses, indicate promising capabilities of the proposed compact contactless system for sub-THz skin imaging applications.