105 GHz Multipath Propagation Measurement and Comparison with 60 GHz in Office Desk Environment for Ultra-High Speed Sub-THz WPAN Systems

This study presents wideband propagation measurements of 105 GHz multipath characteristics, encompassing a full 360° in a real office desktop environment. High-speed wireless personal area network (WPAN) systems operating in such environments represent a promising use case for sub-terahertz (THz) communication systems owing to the short-range nature of such networks. Additionally, selecting a frequency band close to the millimeter-wave spectrum increases the feasibility of sub-THz WPAN systems compared to the widely recognized 300 GHz band, mainly because of the availability of low-cost hardware. However, the multipath propagation characteristics at the 105 GHz band, specifically within a 360° range in a real office desktop environment has not been thoroughly investigated. To address this gap, we evaluate the 105 GHz multipath propagation characteristics, considering both delay and angular profiles and compare them with our concurrent 60 GHz measurements in the same environment. The results indicate a notable distinction between the two bands: a physical partition maintaining personal space causes the multipath power at 105 GHz to deviate by 10 dB relative to the 60 GHz band. Furthermore, our system-oriented analysis highlights the similarity of propagation characteristics in both bands, as nearly all multipath waves at 105 GHz exhibit power levels comparable to those observed at 60 GHz. In both frequency bands, the delay spread extends up to 5 ns, while the angular spread reaches up to 40°. These findings suggest that the current 60 GHz WPAN system standards could be effectively extended to the 105 GHz band for sub-THz WPAN applications.