How to improve the EMC performance of a multilayer board for electrical force measurement switches (PMS)?

Employing multilayer PCBs is one of the most effective ways to improve PMS EMC performance. By providing complete ground and power planes, radiation can be significantly reduced and immunity enhanced. A typical 4-layer board stack-up is recommended as follows: Top (signal), GND (complete ground plane), PWR (segmented power plane), Bottom (signal). A 6-layer board can add two inner signal layers or a second ground plane. Key design considerations include: ensuring an uninterrupted ground plane as a return reference for all signals; segmenting power planes according to voltage values, but maintaining sufficient spacing (>0.5mm) between different power domains; routing high-speed signal lines on inner layers (stripline structure) with ground planes above and below for optimal EMI control; encasing critical signals such as clock signals in ground planes or routing them between two ground planes; creating a shielding wall by placing a ring of ground vias around the board edges; isolating sensitive analog circuits and noisy digital circuits using ground planes; and ensuring that vias with filter capacitors at power inputs are directly connected to both the power and ground planes. Compared to double-sided boards, a well-designed 4-layer board can reduce radiated emissions by 10-15 dB while improving immunity to ESD and EFT.