Most of the crumbling RADOME material I've seen has been on receive-only antennae, because that's what I deal with regularly, so I don't think it's purely a pow

Most of the crumbling RADOME material I've seen has been on receive-only antennae, because that's what I deal with regularly, so I don't think it's purely a power thing. My working hypothesis is more in line with your (1), that plasticizer is the major absorbing component of the plastic, so to make RADOME plastic you just leave out the plasticizer and live with crumbly plastic. But I'm no polymer chemist, so that's really just speculation.