Meh, they need to use gravity waves; not affected by dielectric constant. Maybe a spinning mass that is frequency modulated. I just need to patent that and be funded by some wealthy traders.
Seriously though, I’m surprised they are not using direct path, deeply buried air-line coax. Has to be TEM propogation or else group delay is too high, so rectangular waveguide won’t work. Circular may work; I need to brush up on my EM.
Seriously though, I’m surprised they are not using direct path, deeply buried air-line coax. Has to be TEM propogation or else group delay is too high, so rectangular waveguide won’t work. Circular may work; I need to brush up on my EM.