The radome of course has a say in F22A’s stealth. It is made from composites, and composites are generally transparent to RF waves. With metal nets applied, it deflects RF waves with wavelength bigger than the meshes. By calibrating the mesh size around the max wavelength of its radar emission, then the radome thus plays like a bandpass filter.

BTW, effective steering angle of AESA is just around 60o radian offboresight.

So with the apply of carefully-computed metal nets it will reduce the returning signals that is emitted from the hostile’s fighter which used radar bands such as L-band. But it the radome with metal nets might not help to reduce RCS of the radar panel if the hostile fighter uses similar X-band radar?

If fact, ALR 94 is considered the most sophisticated equipment of the Raptor, even more than the APG 77. Certainly, more expensive. If an ennemy fighter does emmit the ALR 94 will pick at greater distance (Sweeteman said ~ 450 km in the case of a fighter radar). It will geolocate the target, not only finding the direction as a “normal” RWR, but also the distance and speed. Closer,(that means within the AMRAAM range) ALR 94 could cue the AMRAAM without using the APG 77. Hardly “basicallly a RWR”…

So the ALR 94 system is like a passive sensor with multiple antennas that detects the incoming signals of hostile fighter and rely on its computing power to triangulate the relative position and information of the hostile fighter. And then this information is feeded to the radar control computer to narrow the beam to those suspicious point where the signals come from, minimizing the radar emission to protect the F-22 from passive sensor?
How will this system be affected by different wavelengths that the hostile fighter used?
Thanks you.

One thing about AESA radars are that the beams they emit are electronically steerable. This allowed the actual radar panel to be physically tilted slightly upward without impeding performance while at the same time deflecting hostile radar emissions that bounce off the F-22 upwards and away from the emitting aircraft’s receiver.

Hi mabie
Thanks for answer, that makes more sense now how the radar of F-22 will not become a reflective area. So because of that, the nose of F-22 might not have any other interesting feature except its shape? The main RCS-reduced feature of the radar is from the design of the radar itself and may be some limited application of RAM on the nose since the nose must allow radar signals to go through it?
If it’s the case, is it easier for an aircraft to fly at higher attitude to get better signature return from the F-22 since the F-22 radar panel is slightly upward (60 degrees) ?

From the above article

So is the Frontal RCS set to reduce again in PAK FA and that it would be effective only at higher altitude? May be one more reason why they looked for a powerful engine

I think he refered to the plasma screen that is used to reduce the RCS of the radar panel on the airplane and at the same time the radar can still be used. This technique is mentioned in here:
http://forum.keypublishing.co.uk/showthread.php?t=51518
That makes me feel pretty skeptical about RCS number of F-22 also because I am not sure what kind of treatment was used on F-22 nosecone to make sure that the signals from the APG-77 can go through the nose, doing its job and at the same time the radar does not become a huge reflective area that increase the RCS of F-22. :confused: