Heatsink Preselection Chart to Minimize Radiated Emission in Broadband on the PCB

In this article, the type of heatsinks and the horizontal/vertical orientation of them on the printed circuit boards are investigated to reduce electromagnetic interference (EMI) effects caused by the heatsink on the electronic components on the mainboard. The circular, rectangular, and square heatsinks with the equal base area are designed, simulated, and measured in the 1–10 GHz band. All parameters such as the reflection coefficient, electric field values, and radiation pattern are obtained and compared with each other to specify both selection priority of heatsink type and its orientation in a certain frequency range. As a novelty, both the effect of heatsink type and its orientation on EMI performance is investigated to prepare a heatsink selection handout by using simulation and measurement results. While the radiation emission (RE) of the circular type is the lowest between 1.8–3.6 and 5.8–7.8 GHz bands, the RE of the rectangular one is the lowest in 3.6–5.8 and 9.2–10 GHz. Also, for 1–10 GHz range, horizontal orientation is preferred for 10% of the whole frequency region, while vertical orientation is better for 24% regardless of the heatsink type.