This paper presents sub-Terahertz (THz) radio propagation measurements at 142 GHz conducted in four factories with various layouts and facilities to explore sub-THz wireless channels for smart factories in 6G and beyond. Here we study spatial and temporal channel responses at 82 transmitter-receiver (TX-RX) locations across four factories in the New York City area and over distances from 5 m to 85 m in both line-of-sight (LOS) and non-LOS (NLOS) environments. The measurements were performed with a sliding-correlation-based channel sounder with 1 GHz RF bandwidth with steerable directional horn antennas with 27 dBi gain and 8\degree~half-power beamwidth at both TX and RX, using both vertical and horizontal antenna polarizations, yielding over 75,000 directional power delay profiles. Channel measurements of two RX heights at 1.5 m (high) emulating handheld devices and at 0.5 m (low) emulating automated guided vehicles (AGVs) were conducted for automated industrial scenarios with various clutter densities. Results yield the first path loss models for indoor factory (InF) environments at 142 GHz and show the low RX height experiences a mean path loss increase of 10.7 dB and 6.0 dB when compared with the high RX height at LOS and NLOS locations, respectively. Furthermore, flat and rotatable metal plates were leveraged as passive reflecting surfaces (PRSs) in channel enhancement measurements to explore the potential power gain on sub-THz propagation channels, demonstrating a range from 0.5 to 22 dB improvement with a mean of 6.5 dB in omnidirectional channel gain as compared to when no PRSs are present.

翻译：本文介绍了在四种不同布局和设施的工厂中进行的142 GHz亚太赫兹无线电传播测量，旨在探索面向6G及未来智能工厂的亚毫米波无线信道。我们研究了纽约市地区四个工厂中82个发射-接收位置的空间和时间信道响应，覆盖了5米至85米的距离，包括视距和非视距环境。测量采用基于滑动相关的信道探测仪，射频带宽为1 GHz，在发射端和接收端均使用27 dBi增益、8度半功率波束宽度的可操控定向喇叭天线，并采用垂直和水平天线极化，获得了超过75,000个定向功率延迟剖面。针对不同杂乱密度下的自动化工业场景，进行了两种接收高度的信道测量：1.5米（高）模拟手持设备，0.5米（低）模拟自动导引车。结果首次提出了142 GHz室内工厂环境的路径损耗模型，并表明低接收高度在视距和非视距位置分别比高接收高度平均路径损耗增加10.7 dB和6.0 dB。此外，在信道增强测量中，采用平坦可旋转金属板作为无源反射面，探索了亚毫米波传播信道的潜在功率增益，结果显示与无无源反射面时相比，全向信道增益提升范围为0.5至22 dB，平均值为6.5 dB。