A Study on 300 GHz Band Propagation Loss Modeling in the Vicinity of the Human Body Considering the Effect of Clothing

For the Beyond 5G and 6G, the use of the THz band is considered to realize ultrahigh-speed and high-capacity communications. As one of the use cases, we have proposed a virtualized terminal technology to improve the communication speed of the uplink by applying it to the connection between a peripheral device, such as a wearable device, and user equipment (UE). To evaluate the wireless performance of this technology, it is necessary to clarify the characteristics of radio propagation in the vicinity of the human body and construct a propagation channel model. The authors have measured diffraction loss in the 300 GHz band using a human phantom in an upright posture and have shown that while the human body can be approximated by two screens and estimated accurately with a Double Isolated Edge (DIE) model, this accuracy is limited in verification using a real human body and may be affected by clothing. In this work, we clarify the effect of clothing on propagation loss through FDTD simulations and radio propagation experiments in the 300 GHz band via a human phantom. Furthermore, we propose a propagation loss estimation method that takes this effect into account and show that the method can accurately estimate the root mean square error (RMSE) to be approximately 8.35 dB by using measured values from an experiment that assumes a walking motion.