Definition

Electromagnetic Interference (EMI) is unwanted electromagnetic energy that disrupts electronic equipment operation. EMI can be conducted (through power lines or cables) or radiated (through space). PCB design affects EMI through ground plane integrity, high-speed signal routing, and enclosure grounding. Common EMI mitigation includes proper stackup design, controlled impedances, filtering on I/O lines, and keeping high-speed signals on internal stripline layers. Regulatory compliance (FCC, CE) requires meeting EMI emission limits.