J-20 Installed Luneberg Lens Reflector to Enhance Radar signature of the Aircraft
This is an Edwards AFB, F-22 Raptor launching an AIM-9L Sidewinder during testing. If you look aft of the missile’s exhaust plume you’ll notice an odd shape dorsally mounted on the aircraft fuselage. At first you may think it’s a camera that mounted to record launch of the missile but it’s a device meant to enhance the radar signature of the aircraft, called a Luneburg Lens.
The F-35 has 4 luneburg lenses (the picture only shows 3). I think they fly with them most of the time outside of testing.
F-22