Critical Element First: Enhance C-V2X Signal Coverage using Power-Efficient Liquid Metal-Based Intelligent Reflective Surfaces.

This demonstration shows the beam steering capability of a new liquid metal-based intelligent reflective surface (IRS) that operates at the 5.9 GHz frequency band to enhance signal coverage of cellular vehicular-to-everything (C-V2X) communication. The IRS unit cell design leverages the electrical actuation technique to move a liquid metal droplet within a rectangle-shaped microfluidic channel filled with sodium hydroxide (NaOH), which changes the phase and magnitude of the reflection signal, and relies on the liquid metal's high surface tension in NaOH to maintain the droplet position without further energy consumption. A power-efficient sequential control logic with priority over center IRS elements is implemented to promptly steer the reflection beam toward the desired angle before the entire IRS panel is fully configured. The merits of the design are evaluated under a 5.9GHz SISO C-V2X link implemented with a software-defined radio.