In order for constructive or destructive interference to happen in the first place two waves have to be in the same place at the same time, and both waves would have to be going back to the enemy radar for it to matter at all.
Furthermore, the only difference between constructive and destructive interference is half a wavelength.
Buddy, just like the rest of the Chinese members here, you learned of interference from me. So you are not telling me or the forum anything new.
Not only that, you failed to explain
HOW can a reflected wave changed its phase in the first place. The answer is:
Depending on these factors of the structure that created the reflection:
- Shape
- Size
- Material composition
A 'hard' material would be like a metal plate. The plate would not be absorbant enough so the reflected wave would be out of phase from the original wave.
A 'soft' material would be something like wood, water, or layers of different materials aka 'composites. For the last, layers of feathers on a bird is a 'soft' material and is a natural absorber. If there are any reflection, the wave would most likely be in phase from the original.
The shape and size of the structure that created the reflected wave could make the reflected wave either go either way, but usually the smaller the structure compared to the operating freq, the odds are that the reflected wave will be in phase from the original.
How are you able to eyeball some internet pictures of the J-20 and able to tell the difference between the two? How do you prove it's happening at all and that it involves the canards? Most importantly, how do you prove this phenomenon is reflecting radar energy back at the enemy radar?
Any time we have an array of structures, there exists interference from reflections. The more complex the array, the greater the unpredictability of interference.
Cockpits and engines are cavities. Why are cockpits and engines problematic in trying to control RCS? Because of the many structures of different materials and in varying arrays that created unpredictable phase changes and therefore unpredictable instances of both constructive and destructive interference.
Waveguide - Wikipedia, the free encyclopedia
A
waveguide is a structure that guides waves, such as
electromagnetic waves or
sound waves. There are different types of waveguides for each type of wave. The original and most common
[1] meaning is a hollow conductive metal pipe used to carry high frequency
radio waves, particularly
microwaves.
A waveguide is also a cavity. But we do not have a destructive interference issue with waveguides. Why? Because waveguides are empty cavities. If anything, waveguides are conducive towards constructive interference, be it in visible or non-visible spectrum. A length of fiber optic is a waveguide. Same as a square tube in a radar system. So being a cavity alone is not detrimental to RCS control. What matters is anything that is inside the cavity that will create multiple reflections.
What this mean is that the array of the J-20's canards in relation to the fuselage and wings are insufficiently complex to create enough destructive inference to somehow make the canards 'invisible'.
From the front, the canard's leading edge reflected signal will arrive at the seeking radar before the reflected signals from the wing. There will be no interference here. Both canard and wing reflected signals will be out of phase from the original signal but they will be in the same phase with each other. And if we take the Doppler shift into consideration where pulses are compressed as both bodies, aircraft and seeking radar, approaches each other, most likely we will have constructive interference. So your argument that the J-20's canards can be 'designed' in some ways to create destructive interference is not in line with real physics.
As for canard's trailing edge diffraction signals, they will be in phase from the original but they will radiate into free space into all different directions. Some may be detected by the seeking radar, some may collide with the wing's leading edge reflected signal, which probably will be out of phase, and we may (not will) have destructive interference between diffracted and reflected signals. But precisely because the canard is a finite body, it will produce other modes of radiation for the seeking radar to try to detect.
Again...You guys make declarations without providing even reasonable technical explanations to support them but demands others to support theirs. You asked the typical 'How do you know?' of doubters but get offended if the question is turned back to you.
Then confirm that you are narcisistic
So what if I am? Why do you not use your 'aviation study' to prove me wrong? Put me in my place.
Answer the question: What was your 'aviation study' that you claimed to have?
I have exposed your fraud from the very beginning of our discussion, when you claim that Nozzle and airduct of Pakfa should called "Nacelle", then I busted you with citation what nacelle is, and nacelle is not the same as nozzle or airduct. Should i refresh your memory?
You have 'exposed' nothing of me. If you have any aviation experience at all, especially around jets, you would have known that the word 'nacelle' is often casually used to describe not just the engine housing but the entire structure of housing and engine.
If you now admit that you need measured data, then why you drag rubbish like the above?
Just admit it that static canard of J-20 could also contribute relatively low RCS compared to other object in other 5 gen a/c (gap, bump, round nozzle)
It is funny that you demanded measurement data of me by way of your questions but consistently refused to provide nothing more than opinions that the J-20's canards are irrelevant.
Read this...
Fundamentals of Stealth Design & Concepts of RCS Reduction | Page 3
If you have any 'aviation study' at all, especially in the field of avionics and particularly of radar, it would not matter what I claimed of myself and what I may say. You should be able to provide the readers with at least a basic but reasonably detailed explanation of the principles involved to support your claim.
So what was your 'aviation study'?
