PCB Crosstalk Reduction and Multi-Objective Optimization Using Localized Ground Guarding

This research investigates an area-efficient localized ground guarding methodology for reducing electromagnetic crosstalk between closely spaced printed circuit board (PCB) traces. Conventional mitigation techniques, including increased trace separation and continuous grounded guard traces, can reduce unwanted coupling but introduce significant penalties in routing area, copper utilization, and ground-via requirements. Five representative microstrip configurations were designed in EasyEDA and evaluated using an electro-physical behavioral coupling model implemented in MATLAB. The study examined trace separation, continuous ground guarding, and localized ground guarding on a standard FR-4 substrate. An Adaptive Multi-Objective Search/Optimization (AMOSO) framework was developed to explore 5,000 candidate configurations using guard length, guard segmentation, and ground-via allocation as design parameters. Pareto-front analysis identified 972 non-dominated solutions, illustrating the trade-offs between victim crosstalk voltage, shielding copper area, and ground-via count. The results indicate that a 20 mm localized guard achieves an 83.77% reduction in peak crosstalk relative to the tightly coupled 0.2 mm baseline, closely matching the 83.67% reduction obtained with a 50 mm continuous guard. This reduces guard copper area by 60%. A balanced Pareto-optimal candidate with a 5.05 mm guard and two ground vias achieves a 27.84% reduction in crosstalk relative to the 1.0 mm unshielded baseline, using only 1.52 mm² of shielding copper area. This represents an 89.87% reduction in copper area compared with continuous guarding. The work presents a systematic approach to balancing signal integrity, PCB routing density, and grounding-resource utilization in high-density PCB layouts.