Experimental and theoretical investigation of terahertz channel propagation through vehicle windows

Terahertz (THz) communication technology has emerged as a promising candidate for next-generation vehicular networks by enabling high-speed data transmission and low-latency performance. However, it faces significant challenges from channel propagation through vehicular components, such as signal attenuation through window glass, blockage by metallic pillars and vehicle body, and complex reflection and scattering effects from multilayer window structures. This article presents a systematic investigation of THz channel propagation through vehicle windows, examining both static and dynamic scenarios through extensive experimental measurements and theoretical modeling. Using a precision measurement system operating at 120–165 GHz and 220–320 GHz frequency bands, we characterize power loss through single and dual-layer vehicle window glass under various window open-close configurations. We develop and validate theoretical models, based on multilayer Fresnel theory, for both single and dual-layer configurations, achieving excellent agreement with experimental measurements across varying frequencies and incidence angles. These findings provide essential insights for optimizing THz vehicular communication systems, particularly regarding antenna placement and link budget calculations.