How to minimize the grounding impedance of a concentrator?

Excessive high-frequency impedance in the concentrator grounding system can lead to poor noise discharge and filter failure. Minimizing impedance requires optimizing conductors, connection points, and frequency characteristics. The grounding conductor should be a flat copper busbar or braided strip with a large surface area, and its length should be as short as possible. Paint and oxide layers must be removed from connection points, and toothed locking washers or conductive paste should be used to ensure direct metal-to-metal contact.

The PCB ground plane should be complete and thick (2oz copper thickness recommended), and extensive use of grounding vias (spacing <λ/20, less than 15cm for 100MHz) should be used to connect multiple ground planes. The system should employ a star or grid grounding structure. Measured with an impedance analyzer, the impedance from the internal critical circuit ground to the chassis ground terminal should be less than 100mΩ at 10MHz. Low-impedance grounding ensures rapid discharge of surge and ESD currents, protects core circuitry, and improves the effectiveness of filters and shielding.