How to reduce impedance during high-frequency grounding of a power line carrier PLC?

Reducing the high-frequency grounding impedance of power line carrier PLCs requires attention to ground plane design, via layout, and material selection. A multi-layer PCB design with a dedicated ground layer (≥35μm thickness) is used to minimize ground plane resistance. High-frequency grounding vias are arranged in an array with a 0.3mm diameter and 1.5mm spacing, ensuring full connection between the vias and the ground plane to reduce inductance. Low-dielectric-constant substrates (e.g., FR-4, Dk=4.4) are used to reduce signal delay. For system grounding, a short and wide grounding band is used, with a length less than λ/10 (λ being the highest frequency wavelength) and a width ≥5mm. A 100pF high-frequency capacitor is connected in parallel along the grounding path to provide a low-impedance path. During testing, a vector network analyzer is used to measure the grounding impedance; at 100MHz, the impedance should be less than 0.5Ω. Optimization can reduce high-frequency ground noise by 15dB, improving carrier signal quality.