The EMI shielded room is an enclosure designed according to the principle of the "Faraday cage". It mainly uses various shielded materials to form a system, which can block the indoor and outdoor radio signals and ensure that the external radio signals will not interfere with the interior of the shielded room. But the signals inside the RF screen room will be reflected and superimposed on the inner wall. There are four types of electromagnetically shielded rooms: steel plate assembly type, steel plate welding type, steel plate directly attached type, and copper mesh type.