How to reduce EMI leakage in motion controller MC vias

To reduce EMI leakage caused by vias on the motion controller MC PCB, its design and layout need to be optimized. Unnecessary vias should be minimized, especially layer-change vias on high-speed signal lines. For critical signals, microvias or back-drilling techniques should be used to remove useless via studs, reducing signal reflection and radiation. Multiple parallel vias should be used on power and ground networks to reduce impedance and suppress power supply noise radiation.

Grounding vias should be placed near each signal via to provide a path for return current, especially near clock lines and high-speed buses. Avoid placing vias directly below strong radiation sources such as crystal oscillators and antennas. The via aperture should match the pad size to avoid forming large parasitic antenna structures. On the ground plane, via arrays can be designed to form local electromagnetic shielding cavities. The impact of vias on radiation should be analyzed using 3D electromagnetic field simulation, and their number and location optimized. Finally, radiated emission tests should be conducted to verify the optimization effect.