Heatsink grounding effect on radiated emission of electronic device

Heatsink is an indispensable component in electronic device. However, containing emissions from heatsink is rapidly becoming a necessity caused by higher power levels and faster clocking of digital circuits, it affects the sensitive circuit. Some grounding schemes of heatsink are presented and calculated applying the FDTD method. It is shown that different grounding point affect the electromagnetic characteristic of a heatsink differently,. and more grounding points do not mean the improvement of electromagnetic characteristic. Considering four grounding points, four edge centered ground points is selected for a small electromagnetic field.