An Initial Study of Human-Scale Blockage in sub-THz Radio Propagation with Application to Indoor Passive Localization

TL;DR

This study investigates how human bodies block sub-THz radio signals indoors, analyzing effects on channel response and impulse behavior, with implications for device-free localization and RF sensing.

Contribution

It provides the first empirical analysis of human body blockage effects in sub-THz frequencies, advancing indoor RF sensing and localization techniques.

Findings

Body blockage significantly alters channel response in sub-THz bands.

Discrimination of micro-movements improves localization precision.

Sub-THz frequencies offer higher sensitivity for detecting human presence.

Abstract

This paper empirically investigates the body induced electromagnetic (EM) effects, namely the human body blockage, by conducting indoor measurement campaigns in the unexplored sub-THz W-band (75-110 GHz) and G-band (170-260 GHz). The proposed analysis focuses on both the alterations of channel frequency response induced by body presence, fully or partially obstructing the line-of-sight (LoS) between transmitter and recevier, as well as on the channel impulse response (CIR) for selected movements of the target, i.e. crossing the LoS of the radio link. Modelling of large scale parameters is also presented using a phantom body object. The proposed study has applications in device-free radio localization and radio frequency (RF) sensing scenarios where the EM radiation or environmental radio signals are collected and processed to detect and locate people without requiring them to wear any electronic devices. Although preliminary, the study reveals that discrimination of the blockage micro-movements is possible, achieving higher precision compared to classical RF sensing and localization using cm-scale wavelengths (2.4-6GHz bands).