Experimental Observation of Polarization-Induced Asymmetric Scattering from a Concrete Surface at 100 GHz

Terahertz (THz) bands offer extremely wide bandwidth and are attracting increasing interest for future wireless backhaul systems. However, THz propagation is highly sensitive to surface scattering, because the short wavelength enhances the sensitivity to surface roughness. This paper experimentally investigates angular scattering from a concrete surface at 100 GHz under ±45° polarized incidence. The measured scattering distributions exhibit a clear asymmetry with respect to the incident plane. Although pure TE (transverse-electric) and TM (transverse-magnetic) polarized incidences produce symmetric scattering patterns for statistically isotropic rough surfaces, asymmetric scattering appears under ±45° polarized incidence and the observed asymmetry is well reproduced by numerical simulations based on a stochastic function approach (SFA). The results demonstrate polarization-induced asymmetric scattering and confirm the validity of SFA for vector-wave scattering in sub-THz propagation environments.