The passive capabilities of an AEW are well in excess of those of a Rafale. Not to mention those of 800+ F-35s, and there are space-borne radar systems too. As regards a J-20 getting close enough, I'm not convinced.For all the mockery the j-20 gets its RCS is somewhere near 0.01-0.1 sqm RCS at worst. That is good enough for the j-20 to get close enough to fire it's pl-15 on a superhornet or E-3. The question is whether the Americans can reliably detect the j-20 without using radars like the Rafale does.