Hi, Is there a way to run Antenna Check on analog designs or this check is already done inside the DRC?

In magic, it's done separately from DRC; there's an

antennacheck

command. In klayout, it is in the DRC deck, but it might be a separate DRC deck depending on the implementation---I don't remember how it's done in sky130 or gf180mcu. You can check the scripts in the precheck repository to see what they do.