Electromagnetic skins (EMSs) have been considered as boosters for communication performance, from coverage to capacity. The vast majority of the scientific literature considers reconfigurable EMSs, a.k.a. reconfigurable intelligent surfaces, whose phase configuration can be dynamically changed in time as needed. Differently, this work considers low-cost static passive curved EMSs (CEMSs) to be lodged on car doors to alleviate the blockage issue in vehicular networks. CEMSs are pre-configured during the manufacturing process, following the shape of the car door, and they are designed to make car doors behave as anomalous mirrors, and vehicles to operate as opportunistic passive reflectors. This paper delves into the optimization of the CEMS phase profile knowing the coarse a-priori distribution of incident and reflection angles onto the CEMS, as a function of the vehicular traffic pattern. A penalty-based method to optimize both the average spectral efficiency (SE) and average coverage probability is benchmarked against a novel lower complexity and physically intuitivemodular architecture, employing a codebook-based discrete optimization technique. Our numerical results show that whenever the direct path is blocked, by smart preconfiguration of the CEMS, average SE and coverage can be significantly enhanced.

In future 6G millimeter-wave/sub-THz vehicle-to-everything communication systems, vehicles are expected to be equipped with massive antenna arrays to compensate for the severe path loss. However, vehicle-to-vehicle (V2V) direct links are prone to blockage by surrounding vehicles. Emerging metasurface technologies enable the control of the electromagnetic wave reflection towards the desired direction to boost communication performance. Reconfigurable intelligent surfaces (RIS), and the pre-configured counterpart intelligent reflecting surfaces (IRS), are promising low-cost relaying systems for 6G. This paper proposes the usage of conformal metasurfaces (C-RIS or C-IRS) deployed on vehicles’ body to mitigate the blockage impact by creating artificial reflections, compensating for the non-flat shape of the vehicle’s body with proper phase patterns. We analytically derive the phase pattern for a cylindrical C-RIS/C-IRS, accounting for the shape of the car body, which generalizes the conventional planar ones. We propose a novel design for optimally pre-configured C-IRS proving its benefits in a V2V highway scenario. The traffic simulation results show a reduction of blockage probability by 20% for C-IRS and 70% for C-RIS as a benchmark, as well as a remarkable improvement in average signal-to-noise ratio by 10–20 dB for C-IRS and 30–40 dB for C-RIS.