Wideband Transmissive Programmable Metasurface for Adaptive Millimeter‐Wave Beamforming

Abstract

Programmable metasurfaces provide a promising paradigm for the beamforming of electromagnetic waves in the fifth‐generation (5G) and sixth‐generation (6G) wireless communications with low cost and low complexity. However, most of the existing researches are focused on the sub‐6 GHz spectrum, which limited the gigabits per second (Gb s−1) high‐speed data transmission on future wireless network. Additionally, as a step forward in the development of intelligent metasurfaces, extra peripheral devices are often required to sense environmental variations for self‐adaptive modulations. Here, a wideband millimeter‐wave programmable metasurface is presented for peripheral‐free self‐adaptive signal enhancement in 5G/6G wireless communication. The proposed transmissive programmable metasurface consists of meta‐atoms, exhibiting efficient transmission (1 dB loss) and a stable 1‐bit phase difference from 23.7 to 32.1 GHz, effectively covering the desired 5G millimeter‐wave frequency bands: N257, N258, and N261. By integrating the self‐adaptive algorithm based on received signal intensity into the controller, the programmable metasurface can self‐adaptively establish an optimal or acceptable channel according to the predefined threshold values. To evaluate the performance of the prototype, an experiment on wavefront modulation was first conducted in a microwave chamber, verifying the wideband beamforming performance of the programmable metasurface. Moreover, self‐adaptive signal enhancement and millimeter‐wave wireless communication experiments were conducted in indoor environments, showing a maximum signal enhancement of 21.4 dB and a significant improvement in constellation. The proposed self‐adaptive wideband programmable metasurface demonstrates high potential for application in 5G/6G millimeter‐wave wireless networks.