From a couple of points:
- The J-11D uses an AESA developed by the 14th Institute (NRIET)
- The 14th Institute also won the J-10C's radar contract because
it could pack more T/R modules into a tight radome volume than the 607th Institute's radars. Keep this note in mind.
- The 607th Institute developed the radar for the J-16, which allegedly (
from published documents) could track a
1 m^2 target from 450 km (supposedly using L-band, but I could be wrong on this account)
- The Su-35's Irbis-E can track a
3 m^2 target from only 350 km
- The logic goes that if the 607th Institute's radar could already outstrip the Irbis-E in terms of detection range, then a radar from the 14th Institute, which can pack more T/R modules into a certain space, must be on the same level at the very least
Of course, detection range is by no means the only parameter by which radars should be judged, but in terms of BVR warfare, an early detection advantage is essentially what tips the battle in one's favor.
In this assessment I assumed that both the Su-35 and J-11D adopted similar levels of composite materials and radar absorbent coating (although I question how much that would really matter). I also assumed that both aircraft generate enough thrust to meet the power requirements of their respective radar systems.