Wideband Channel Measurement and Characterization on a Computer Motherboard

Interconnections among chips on computer motherboards currently rely on wired structures, which limit the development of the scalability and computing ability of computers due to difficulties in design and maintenance. To overcome this, THz wireless communications are envisioned as a good solution, with abundant spectrum resources and submillimeter-length antennas. However, one major challenge lies in the channel characterization and modeling in the THz band on computer motherboards. For instance, the influence of the objects on computer motherboards, such as the ground plane, memory chips, etc., needs to be evaluated carefully. In this paper, measurement campaigns are conducted in 100-140 GHz band using a vector network analyzer (VNA)-based channel sounder. Several propagation cases, including the line-of-sight (LoS), none-LoS(NLoS), and reflecting NLoS (RNLoS) cases, are measured and studied. The channel characteristics, such as path loss, delay spread, as well as penetration and reflection losses, are calculated and analyzed. In particular, reflections of the ground plane and vertical memory chips induce multipath effects in the LoS case. Moreover, the vertical memory chip can serve as an effective reflector to improve the link quality in the NLoS case by nearly 30 dB improvement. The insights given in this work can offer guidance to system designs for THz wireless communications on computer motherboards and THz chip-to-chip communications.