The military has been using radar invisible aircraft for years, but so far their production has been costly and complicated. However, Chinese scientists have developed a completely new kind of material that effectively absorbs radar waves over a wide frequency range, significantly reducing the risk of radar detection.
Currently used to build invisible radar for fighters uses a special paint absorbing radar waves, and also develops a suitable construction of the plating of the machine to further minimize the risk of beam bounce directly into the radar. However, this is a complicated and extremely expensive process, so it is not applicable to any fighter model.
However, the Chinese scientists at the University of Science and Technology Huazhong have developed a special material called AFSS, which measures only 7.8 mm in thickness, but is capable of absorbing radar waves in a wide spectrum of frequencies.
The first 7 mm coating is a honeycomb material that supports the outer layers and separates them from the metal surface of the aircraft. The next layer is 0.04 mm thick and uses copper semiconductors and the last layer is called FR4. This material is used to print electronic circuits that have the ability to absorb a wide range of radio waves.
The material was designed to absorb radar waves in the UHF frequency range (0.9 to 1.9 GHz), that is, in the scope of modern military radar systems. And thanks to its small thickness, it can be successfully used on fighters because there are no such limitations as the solutions used so far.