A polymer bonded gridded box EMI shielding method based on FEM for high speed railway

Current passing through conductor in free space of air generates magnetic field which could interfere with the other apparatus nearby or even interrupt it. Inversely, the electromagnetic sources could also be affected by reaction filed or field generated from else. Therefore, the equipment needs to be designed to both blocking and tolerating the electromagnetic radiation. The electromagnetic interference could be mitigated or minimized by many techniques like filtering, earthing, or shielding. Especially in high speed railway, enclosing dc and ac system, high power and lower power system into a limited area requires the equipment generates less electromagnetic Interference (EMI) and could perform against the interference by the other apparatus. Metal box shielding is a method when the circuit design alone cannot satisfy the requirement that the equipment could stand against the environmental EMI or emanating from the equipment. This paper presents a polymer bonded gridded box shielding method which is light, flexible, material saved and suitable for high and low frequency shielding by employing polymer material.