In recent years, intelligent metasurfaces have shown great application potential in intelligent communication and adaptive camouflage due to their adaptive manipulation of electromagnetic (EM) waves without human intervention. With the rapid development of unmanned systems and artificial intelligence, in the design and application of advanced intelligent equipment, enhancing the EM manipulation ability of equipment has become a key challenge to improve the adaptability of various intelligent devices to EM environment and ensure their safe and reliable operation. Especially in the application of intelligent equipment in the fields of autonomous vehicles, aerospace equipment and communication facilities, visible light observation or infrared detection of light windows are required, and the metasurface applied to the light window not only needs to be able to adapt to the changes in the EM environment to manipulate the transmission of EM waves, but also needs to have a wide band of high transparency from visible light to infrared. However, existing intelligent metasurfaces are mainly based on regulating the resistance or capacitance value of lumped elements (PIN diodes, varactor-diodes, etc.) to achieve EM wave manipulation, which usually requires printed circuit boards and surface mount technology for welding, and it is very difficult to achieve high transparency in the visible-infrared broadband. In addition, the actuators and sensors of most intelligent metasurfaces are designed separately, which seriously affects their integration and limits their practical applications. Overall, how to achieve intelligent metasurfaces with broadband optical transparency and high integration remains a major challenge.

The team of Professor Lu Zhengang of Harbin Institute of Technology integrated patterned VO₂ and metal grid resonant unit to form a tunable actuator, and integrates it with transparent broadband microstrip antenna to realize the integration of perceptron and actuator, and further integrates external integrated sensing and feedback modules to build a closed-loop system without manual intervention. The designed transparent intelligent metasurface senses the power of environmental EM wave through integrated transparent broadband microstrip antenna, power detector and field programmable gate array (FPGA), and then the upper computer PC sends corresponding feedback command according to different power signals. The feedback current controls the metasurface switching corresponding to strong reflection (shielding efficiency of more than 24 dB), high transmission (transmission loss of 1.24 dB), and high absorption function (absorption rate of 97 %). Through the use of micrometer-scale patterned VO₂ and metal grid single-layer microstructure, the entire intelligent metasurface achieves a transmittance of more than 80% in the visible to infrared broadband, which has great application prospects in the field of intelligent equipment transparent light windows.

The proposed new transparent intelligent metasurface has high broadband optical transmittance, excellent intelligent switching ability of electromagnetic function, and high integration, which greatly broadens the application range of intelligent metasurfaces, and makes the applications of intelligent metasurface no longer limited to non-optically transparent scenes. It is expected to provide technical support for light windows such as aerospace equipment and intelligent instruments, multi-mode radomes, communications facilities, and other applications requiring adaptive manipulation of electromagnetic waves and high optical transparency.

Fig. 1. Schematic of the optically transparent intelligent metasurface.

Sources：https://spj.science.org/doi/10.34133/research.0334

Chao Xia, Zhengang Lu, Yilei Zhang, Jiubin Tan. Broadband High Optical Transparent Intelligent Metasurface for Adaptive Electromagnetic Wave Manipulation. Research. DOI:10.34133/research.0334

Tag: Advanced Materials