3000 GHz? Coax is usually tested and marked for the highest frequency, usually 3GHz.
FWIW, microwaves, which extend "only" up to 30 ghz, require waveguide to pass from one location to another. It ain't being passed through no steenkeeng coaxial cable. And they require a klystron tube to amplify them.
I worked with this crap when I was in the AF. Power klystrons are right out of a science fiction movie...
3000 ghz, or 3 terahertz, is a totally different animal.