We are 2 french students working on the stealth materials of the F/A 22 raptor and we've read many articles about the reasons of this ability, but we
couldn't find any precise explanation about the materials that constitute the plane (for example what are the RAM made of? and what are their
physical properties?)
Sorry but I don't think that anybody can really help you guys. The F-22s are just coming into service so a lot of the info is still confidential.
It might pay off to have a look at the F-117, the F-22's paint job has many similarities I hear. Anyhow good luck, wish I could have been more
help.