Stealth - the oldest human dream, in ancient myths and legends, the sweeping world "Harry Potter", science fiction films, there is this legend "magic" figure. However, this "stealth technique" has come into our real life. Recently, an international scientific research group composed of Duke University and Southeast University in the United States has successfully developed a "invisible coat", put it on and instantly hide. The research was published in the January 15 issue of Science this year, with Professor Cui Tiejun of Southeast University and Professor David Smith of Duke University co-authoring the paper. Invisible coat like a big yellow towel "invisible coat" in the end what kind? Cui Tiejun said that this invisible coat is actually more like a piece of "invisible carpet". On the outside, it looks like a big yellow bath towel. Put it on an object, the object "disappeared." This invisible coat can make the microwave "turn", Cui Tiejun explained that the electromagnetic wave into the invisible coat after bending in which walking around the invisible coat wrapped objects, unchanged shooting, as the wrapped object does not exist at all . In short, invisible coat can guide the electromagnetic "steering" to avoid the detection of instruments to prevent objects from being found by electromagnetic waves. It's like the water in a stream, and when it passes a stone, the stream turns around the stone and closes again, moving on like a stone without encountering it. This invisible property has special requirements on the refractive index of the material, which can only be achieved by using new artificial electromagnetic materials. Change the "coat" structure to achieve stealth New artificial electromagnetic material in the end what is it? "There is no natural invisible material in nature." Cui Tiejun told reporters that the new electromagnetic material is artificial material, that is, the macroscopic basic units with specific geometric shapes are periodically or non-periodically arranged, or implanted into the material body . The basic unit structure inside the material directly determines the characteristics of the electromagnetic material. People can control the properties of the material by artificially designing the structures inside the material. Cui Tiejun also introduced that the current design of this "invisible coat" and "invisible carpet" is actually not difficult, as long as the use of printed circuit board technology on it, therefore, the cost is not high. It is still a long time to avoid the human eye. However, this "invisible coat" can only be stealthy in the field of microwaves. It can not avoid the visible light. In other words, it can not achieve the goal of " Stealth "effect. Cui Tiejun told reporters that it is still quite a long time to design a coat that can avoid visible light. "Invisible material" also potential applications Professor Cui and foreign experts in this research is not limited to this "invisible coat", he also told reporters, "In fact, we have prepared a precise design of new artificial electromagnetic materials (Or metamaterials) software that uses these metamaterials to design three-dimensional invisible coats, invisible rugs, new antennas, etc. "What can be done with our invisible materials in the end? Cui Tiejun said with a smile, "invisible coat" and "invisible carpet" has many important potential applications. For example, in the military, aircraft, tanks and other targets can disappear completely in the enemy's eyes through stealth technology. In civil applications, similar principles can be applied to wireless communications, medical imaging, non-destructive testing, and automotive collision avoidance radar.