In this paper, a large-scale . RLC filter is proposed with the aim to suppress common mode (CM) noise that takes place within parallel conducting plates in high power systems. For this purpose, the filter model was created in COMSOL Multiphysics 6.0, run Maxwell’s equation for electric field in frequency domain, and evaluated with good results in derived equations for CM transmission coefficients using CISPR 17 methods. The proposed structure with shielding enhanced the simulations CM noise (< - 25 dB) within the range of 1 MHz to 220 MHz. As an application, variations in phase (0°-180°) and amplitude device output obtained along frequency.