That isn't exactly correct.
A complex object will reflect radar wave in many ways
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But in general they can be grouped into:
Specular return: this is the most significant form of reflection, surface acts like a mirror for the incident radar pulse. Most of the incident radar energy is reflected according to the law of specular reflection ( the angle of reflection is equal to the angle of incidence).
Traveling/Surface wave return: an incident radar wave strike on the aircraft body can generate a traveling current on surface that propagates along a path to surface boundaries such as leading edge, surface discontinuous …etc, such surface boundaries can either cause a backward traveling wave or make the wave scattered in many directions
Diffraction: wave striking a very sharp surface or edge are scattered instead of following law of specular reflection.
Creeping wave return: this is a form of traveling wave that doesn’t face surface discontinuous and not reflected by obstacle when traveling along object surface , thus it is able to travel around the object and come back at the radar. Unlike normal traveling wave, creeping wave traveled along surface shadowed from incidence wave (because it has to go around the object). As a result, the amplitude of creeping wave will reduce the further it has to travel because it can’t feed energy from the incident wave in the shadow region. Creeping wave mostly traveled around a curved or circular object.
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When the object size is at least 10 times the wavelength, we say it is in optical region, in this regime, specular mechanisms dominate. In this regime, “surface wave” mechanisms are small contributors to RCS, but are still present. If the wavelength is small relative to the surface, these waves are weak and their overlap will generate maximum backscatter when the radar signal is at grazing angles. When these currents encounter discontinuities, such as the end of a surface or change in material or sharp edge, they abruptly change and emit edge waves or edge diffraction. That why DSI is stealthier than a variable inlet, because DSI can be smooth while variable inlet must have gaps and discontinuities
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To reduce the effect of discontinuities scattering at panel gaps or trailing edge, one common solution is serration
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When the wavelength approach the size of the object (for simple object such as a sphere that mean 1 < 2πa/λ < 10 ) we say the object is in Mie region, in this region, a creeping wave travels around the object and back towards the receiver where it either interferes constructively or destructively with the specular return. So it can either increase or reduce the total RCS value. With that said, the magnitude of the creeping wave return is much smaller than specular return even in this case.
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Some objects are easier to curve around than the other, stealth aircraft are designed in a way that would minimize the creeping wave return coming back to the source, such as not using pure cylinder shape
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Stealth isn't invisible, stealth is making your vehicles harder to detect to the enemy so you can attack them first. Everything is stealth if you stay far enough and nothing is stealth if you are close enough. The goal of stealth design is to make this distance shorter.
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