How to reduce impedance during high-frequency grounding of intelligent low-voltage monitoring units?

High-frequency grounding impedance reduction takes into account the skin effect and parasitic inductance. A multi-layer grounding structure is adopted: a 1oz thick copper surface layer and a complete ground plane inner layer. A dense array of vias with a spacing of 2.5mm and a via diameter of 0.3mm is used. Multiple-point connections are used for grounding pins. A local grounding island is placed below high-frequency devices. Power supply decoupling uses a multi-value capacitor in parallel: 10μF + 1μF + 100nF + 10nF. A flat copper strip is used for the grounding wire. With this design, the grounding impedance is less than 0.1Ω at 100MHz, high-frequency noise discharge efficiency is improved, and radiated emissions are reduced by 12dB.