While last month we talked about the Taranis Drone that attains ‘rudimentary’ stealth by virtue of its high speed, the technological scope of stealth is far more complex than sheer velocities. To that end, a group of Chinese researchers have developed a special composite aircraft material that can actually absorb microwaves at variant ranges of frequencies. Christened aptly as the ‘Active Frequency Selecting Surface’ (AFSS), the thin-material is touted to effectively react and adapt to different radar frequencies, thus allowing for dynamic stealth that more akin to chameleon skins.
Now in conventional terms, most of our current stealth technology is primarily depended on two factors. The first of these entails the incorporation of unique geometry that can reflect radio waves at certain angles. The second and more advanced ambit relates to an exotic material that can absorb radar signals, and transform them into ‘non-escaping’ heat energy, thus making the aircraft nigh invisible (this tech is observed in F-22 and F-35 fighters). However while these scopes are potent enough for radars in the Super High Frequency (SHF) range, they are not entirely effective for ultra-high-frequency (UHF) signals. Incredibly enough, such long wavelength radars are already being planned to be integrated into fire control systems by some military forces around the world – which could affect the current stealth technologies with inadequacy.
But in this case, the Chinese scientists have opted for a composite stealth material which is claimed to be ‘loaded with lumped elements’. In that regard, the ultra-thin specimen is just around 7.8 mm (or 5/16 of an inch) in thickness – with 0.8 mm comprising FR4 (a material used in printed circuit boards); 0.04 mm comprising a surface copper-and-semiconductor; and 7 mm comprising a sturdy honeycombed material that provides foundation for the upper layers while also allowing for segregation from the actual metal surface of the aircraft. When translated to figures, the thin material was found to ‘swallow’ radio frequencies ranging from 0.7 to 1.9 GHz in a reactive manner, which resulted in the reduction of reflectivity within the range of 10 to 40 dB.
Lastly, the progressive nature of the scope begs one question – why did the Chinese researchers divulge so much information about a military technology that can be a potential game-changer in tactical sorties of the future? Well one of the reasons of making their breakthrough public could relate to its assessment by experts from around the globe. This in turn could lead to findings of the proverbial ‘chinks in the armor’ that would aid the Chinese scientists to rather improve the core technology.
The study was originally published in the Journal of Applied Physics.
Via: Ars Technica