3d/4d Printed Tunable Electrical Metamaterials With More Sophisticated Structures

As a novel and attractive advanced manufacturing technology, three-dimensional (3D) printing can realize the manufacturing of devices with more sophisticated structures. Metamaterials (MMs) are a novel material design idea based on the variation of physical structural designs, in order to break through apparent and intrinsic natural laws of matter, and eventually obtain extraordinary material functions. With the development of stealth technology, it has become a hot topic to seek and design radar absorbing materials to realize the high-performance requirements of "thin, light weight, wide and strong". At this time, 3D-printed MMs with various sophisticated structures exhibit great application potential. Recent studies report the development of a wide variety of 3D-printed electromagnetic MMs (EMMs), which are attracting increasing scientific attention. To better advance the design of 3D-printed MMs, it is necessary to fully comprehend the advantages and disadvantages of various printing technologies, and fully understand the latest progress in printed EMMs. Four-dimensional (4D) printing is a combination of 3D printing and smart materials, which unfolds new opportunities for intelligent and customized development in aerospace and electronic devices. The present work reviews the research progress in electrical MMs printed using various 3D/4D printers. Emphasis is placed on the structural design of EMMs, selection of absorbing bases, category of absorbing materials, 3D printing types and EM absorption performance. As the demand for data grows rapidly, 5G wireless mode is developed. Technology from 100 GHz to 1.0 THz frequency bands has great potential in wireless communications for the upcoming 6G. 3D-printed electronic antennas and 5G/6G antennas fabricated by other processes are also briefly summarized. Meanwhile, the article discusses and looks forward to the potential future design and development of 3D/4D printed electrical AMMs for stealth and antenna applications.