Beams of such devices are still far too wide to be detected in other stellar systems.
Even if it covers 1 spherical degree (which is quite narrow for a microwave antenna), that gives an antenna gain (relative to spherical radiation) of only 720. This is peanuts compared to the background noise at interstellar distances. You can forget microwaves, etc and anything shorter than near infra-red. Only such beams can be made slender enough to be detectable at interstellar distances.