RCS measurements based on a fiber-coupled terahertz time-domain spectrum system

Current terahertz devices exhibit low radiation power, and terahertz target scattering characterization measurements are predominantly conducted in indoor environments. Terahertz time-domain spectroscopy (THz-TDS) systems, with their broadband, high sensitivity, and quasi-optical characteristics, are particularly suitable for compact-range scale-model and small-target measuring in indoor environments. By leveraging a fiber-optic coupled transceiver link and compact-range design, a TDS scattering characterization measurement system with a total transmission path exceeding 20 m was implemented in an anechoic chamber. This system successfully measured the high-accuracy radar cross section (RCS) of targets with larger size within the 0.3-2 THz. The RCS of a metallic scale model was measured and compared with simulation results from rapid computational methods to validate applicability. Furthermore, high-frequency scattering theoretical calculation methods for large-scale targets in the terahertz band and the application scenarios of scale-model measurements were explored.