With the widespread popularity of wireless local area networks, radio-frequency wireless signals have gradually become ubiquitous, with the coverage from conventional buildings to high-speed moving vehicles. Now, a natural question arises up: Can the existing wireless signals in the environment be manipulated and recycled in a flexible and inexpensive way? The answer is positive, with the aid of programmable metasurface. Programmable metasurface is composed of an array of electronically-controllable low-loss meta-atoms, which has been proved to be powerful in manipulating electromagnetic wavefronts. In this report, we present a novel approach that environmental wireless signals, such as commodity Wi-Fi signals, can be controllably manipulated by programmable metasurface to achieve what was thought to be impossible. We start by designing a large-aperture programmable phase-binary metasurface, working at 2.4 GHz Wi-Fi frequency band. Then, we present a self-developed efficient algorithm to artificially manipulate the spatial energy distribution of commodity Wi-Fi signals in a controllable way by finding the optimal coding sequences of metasurface. Several experimental results have been provided to show that Wi-Fi signals can be successfully boosted at multiple locations, with a maximum enhancement of signal intensity of 23.5 dB. Further, we develop a proof-of-concept system of massive backscatter wireless communication, which modulates extra information to ambient commodity Wi-Fi signals and achieves data rates on the order of hundreds of Kbps.

      双雅(1993-)，女，陕西人，2021年北京大学信息科学技术学院取得博士学位，现为华东师范大学通信与电子工程学院准聘副教授，研究方向为基于可编程超表面的电磁感知系统、超表面设计等。