Terahertz antenna-channel codesign for integrated sensing and communication in the near field

Abstract

Terahertz (THz) systems in the range of 100 GHz–10 THz combine large apertures and short wavelengths, resulting in an extended radiative near field where spherical wavefronts dominate electromagnetic propagation. In this near-field (NF) realm, classical far-field beam steering and stationary channel assumptions break down, and integrated sensing and communication (ISAC) becomes naturally interpretable as wavefront engineering: the transmit aperture shapes a radiated field to simultaneously deliver data and probe the scene. Such wavefront engineering requires a joint consideration of beam propagation characteristics and realistic environments enabled by large apertures. This paper develops an antenna–channel co-design framework for near-field THz ISAC that couples i) physically grounded channel/environment models with ii) aperture geometry and iii) sensing-communication resource scheduling. This framework creates co-design rules that connect channel characterization and source design, providing a pathway toward scalable THz ISAC systems that are robust in real-world environments.