Hybrid Channel Modeling and Environment Reconstruction for Terahertz Monostatic Sensing

Terahertz (THz) integrated sensing and communication (ISAC) aims to integrate novel functionalities, e.g., environmental sensing, into communication systems. Accurate channel modeling is crucial for the design and performance evaluation of future ISAC systems. This paper presents a novel hybrid channel model and a high-precision environment reconstruction framework for THz monostatic sensing. Vector network analyzer (VNA)-based channel measurements using the directional scanning sounding (DSS) scheme are performed in a laboratory environment at 300 GHz with a 20 GHz bandwidth. A low-complexity space-alternating generalized expectation-maximization (SAGE)-based algorithm is proposed to estimate the parameters of the multipath propagation components (MPCs) and to de-embed the antenna pattern. Leveraging geometric principles, the MPCs are classified into specular and diffuse components. In our proposed framework, the specular components are used for material detection and identification, while the diffuse components are leveraged to enhance geometric environment reconstruction. Demonstrations of both geometrical environment reconstruction and material identification are provided to validate the effectiveness of the proposed approach. This work offers valuable insights into THz monostatic sensing channel modeling and the design of future THz ISAC systems.