I have no problem repeating this:
THERE IS NO SUCH THING AS "COMPLETE STEALTH".
What we have are degrees of observability. For any radar system, there is somethiing called 'maximum effective detection range' and the criteria is
IF the system is able to detect a target %50 of the time at a so-and-so distance. So if I were to spec-ed out a radar system for purchase, when I say to the manufacturer: 'The system must be able to detect a 5m2 target at 200km.' What I really really really mean is that the system
SHOULD be able to guess that at 200km distance, there is a target that is five meters square large and that guess is correct half the time.
Any target can be five meters square large to a radar but the problem for a moving target is
DISTANCE and therefore
WHEN will that body become five meters square large. So if the manufacturer managed to comply with my specs and I encounter an enemy who become five meters square large at 20km it is not his fault. The enemy just happened to be electronically smaller than what my radar is capable of 'guessing' at any distance beyond 20km. So for rhetorics sake you can call it 'complete stealth' since 20km is pretty much weapons release point for lobbing bombs that can also glide some more distance, but technically speaking, nothing is 'invisible'.
As a side note, that maximum effective detection range is factored in with clutter and constant false alarm rate (CFAR) processing...
Constant false alarm rate - Wikipedia, the free encyclopedia
There are dedicated CFAR engineers who retired, to very nice boathouses in the Florida Keys, without touching anything else in their careers. This is a can of worms that is beyond the scope of this discussion. American 'stealth' aircrafts are designed to be in the clutter region and to create CFAR ambiguities in radar systems.