The effect of fin types of the heatsinks on radiated emission on the printed circuit board at S‐C band

Abstract

Heatsinks are widely utilized to maintain the temperature of the electronic circuit components on the printed circuit board (PCB) within a certain range. Even they are thermally used for maximum cooling; they can also act as a source of electromagnetic (EM) radiation, causing EM interference (EMI) to their surrounding elements in certain cases. In this article, the heatsinks with various fin types such as plate‐fin, parabole‐plate fin, square‐pin fin, and circular‐pin fin are designed and fabricated to investigate EMI and thermal performances. The simulated and measured results of the reflection coefficient and normalized radiation pattern are obtained and compared in the S‐C band (2‐8 GHz). The dimension of the heatsink base regarding the patch antenna determines the first resonance frequency (4.75 GHz) while its height regarding the monopole antenna determines the second resonance frequency (6.75 GHz). It is aimed to investigate the effect of fin types of them and their orientation on radiated emission (RE) on the PCB. If the operating frequencies of the circuit elements near the heatsink are in the 2 to 3.4 GHz, 4.7 to 5.6 GHz, 5.6 to 6.15 GHz, and 6.85 to 8 GHz, it is preferable to use pin‐fin type instead of plate fins to reduce the RE from the heatsinks. However, in the 6.15 to 6.85 GHz, plate fins types should be preferred. All heatsinks regardless of fin types in the 2 to 2.2 GHz, 3.6 to 5.6 GHz, and 6.6 to 7.2 GHz should be located as horizontal. However, for 2.2 to 3.6 GHz, 5.6 to 6.6 GHz, and 7.6 to 8 GHz frequency bands, they should be located as vertical. Consequently, while pin‐fin type heatsink is preferred in 50% of the entire frequency band, it is better to use plate‐fin type heatsink in 35% of the band. Regardless of the type of heatsink used, it is significant to place the heatsink horizontally and vertically in 35% and 34% of the frequency band, respectively.

Experimental investigation of forced convection heat transfer for different models of PPFHS heatsinks with different fin-pin spacing

“…in cases where circuit elements are placed around the heatsink, the base part of the heatsink behaves like a patch antenna and the vertical pins and fins on the heatsink will act like a monopole antenna, thereby causing electromagnetic interference (EMI) [ 25 ]. Basyigit et all [ 26 ] studied the effects of fin types of the heatsinks on radiated emission on the printed circuit board at the S–C band. They simulated and compared the effects of operating frequency on heatsinks with different designs such as heatsinks with parabole-plate fin, square-pin fin, and circular-pin fin with different orientations and positioning.…”

Analysis of Electromagnetic Interference for Anti-Medal UHF RFID Temperature Tag in High Power Electronic Equipment

“…Mississippi State University (MSU) analyzed system-level EMI-common mode electromagnetic interference (EMI) from wide-bandgap (WB) power switching in medium-voltage power electronics applications and effectively reduced EMI effects with new circuit configurations and mitigation techniques [31]. European researchers have studied and analyzed the electromagnetic interference of heatsinks on printed circuit boards (PCBs), and the literature states that the shape and size of a heatsink made of metal allows it to generate near-field and far-field radiation such as an antenna and that heatsinks of different shapes and sizes generate radiated electromagnetic interference at different frequencies, which in turn affects the operating performance of the electronic circuits or communication systems around it [32].…”

Experimental Analyses of EMI Noise Separator for CISPR25

“…There are two types of electromagnetic interference (EMI) propagation types. The first of these is emission by radiation, which the EMI source interferes with through the air [4][5][6][7][8][9][10], and the second is the emission by transmission, where the source interferes over the line to which it is connected [11,12]. The form of conducted emission noise is defined by modes in systems.…”