Abstract
Looking back on the development of metamaterials in the past 20 years, metamaterials have gradually developed from three-dimensional complex electromagnetic structures to a two-dimensional metasurface with a low profile, during which a series of subversive achievements have been produced. The form of electromagnetic manipulation of the metasurface has evolved from passive to active tunable, programmable, and other dynamic and real-time controllable forms. In particular, the proposal of coding and programmable metasurfaces endows metasurfaces with new vitality. By describing metamaterials through binary code, the digital world and the physical world are connected, and the research of metasurfaces also steps into a new era of digitalization. However, the function switch of traditional programmable metamaterials cannot be achieved without human instruction and control. In order to achieve richer and more flexible function regulation and even higher level metasurface design, the intelligence of metamaterials is an important direction in its future development. In this paper, we review the development of tunable, programmable, and intelligent metasurfaces over the past 5 years, focusing on basic concepts, working principles, design methods, manufacturing, and experimental validation. Firstly, several manipulation modes of tunable metasurfaces are discussed; in particular, the metasurfaces based on temperature control, mechanical control, and electrical control are described in detail. It is demonstrated that the amplitude and phase responses can be flexibly manipulated by the tunable metasurfaces. Then, the concept, working principle, and design method of digital coding metasurfaces are briefly introduced. At the same time, we introduce the active programmable metasurfaces from the following aspects, such as structure, coding method, and three-dimensional far-field results, to show the excellent electromagnetic manipulation ability of programmable metasurfaces. Finally, the basic concepts and research status of intelligent metasurfaces are discussed in detail. Different from the previous programmable metamaterials, which must be controlled by human intervention, the new intelligent metamaterials control system will realize autonomous perception, autonomous decision-making, and even adaptive functional manipulation to a certain extent.
Highlights
As an emerging research product in the 21st century, or a new type of artificial composite functional material, metamaterials are subwavelength artificial composite structural materials, whose unit size is generally less than half of the working wavelength
This paper aims to review the evolution of electromagnetic manipulation: from tunable metasurfaces to active programmable metasurfaces and intelligent metasurfaces
3, we introduce the concept and design method of the coding metasurface, and describe in detail the structure, coding method, and far-field results of the active programmable metasurface based on PIN diodes, active amplifiers, transistors, thermistors, and photoresistors
Summary
As an emerging research product in the 21st century, or a new type of artificial composite functional material, metamaterials are subwavelength artificial composite structural materials, whose unit size is generally less than half of the working wavelength. The concept of electromagnetic (EM) metamaterials originated from a Russian paper published by Veselago [1], a scientist of the former Soviet Union, in 1967. Veselago proposed left-handed materials, which have negative dielectric constants and magnetic conductivity [2,3,4]. This breakthrough concept subverted people’s cognition of traditional electromagnetic materials, the theory received little attention at that time because such double-negative materials could not be obtained in nature, and it was difficult to be verified by experiments. With three-dimensional structure, electromagnetic metamaterials have unique physical properties that traditional materials do not have, such as inverse
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
