What impact does the material of the shielding layer (copper/aluminum) have on the high-frequency suppression effect of common-mode inductance?

The conductivity of copper (approximately 5.8×10⁷ S/m) is much higher than that of aluminum (approximately 3.77×10⁷ S/m). At high frequencies, copper can more effectively reflect or absorb external high-frequency electromagnetic fields through the eddy current effect, reducing the impact of common mode inductance on external interference and simultaneously minimizing the interference of its own electromagnetic radiation on the outside world. Aluminum, with its lower conductivity, experiences relatively greater eddy current losses at high frequencies, resulting in weaker shielding effectiveness and slightly inferior reflection/absorption capabilities for high-frequency electromagnetic fields. Therefore, under the same structure, the copper shielding layer exhibits superior high-frequency suppression effects for common mode inductance. However, aluminum has a lower density and lower cost. If high-frequency suppression requirements are not extreme, aluminum can be considered as a lightweight and low-cost option.