Akademik Veri Yönetim Sistemi
Journal of the Faculty of Engineering and Architecture of Gazi University, cilt.38, sa.2, ss.733-742, 2023 (SCI-Expanded)
The miniaturization of the circuit as a result of the increase in the operating frequencies of the PCB circuit elements increases the amount of heat in the environment. Metal heatsinks are widely utilized for the transfer of an increased amount of heat. However, the heatsinks cause radiated electromagnetic (EM) emissions at certain frequencies. These emissions negatively affect the operating performance of the circuit elements around the heatsinks. The maximum E-fields radiated from circular heatsink for four different feeding points are given in Figure A. Purpose: This study aims to investigate the effect of different feeding points on EM behavior of rectangular and circular heatsinks with an equal base area in the 1-10 GHz band. Theory and Methods: The rectangular and circular heatsinks are designed as shown in Figure A. These heatsinks are cut into blocks made up of 6061 aluminum material and manufactured via a CNC milling machine. Ground plane and coaxial waveguides are used in the simulation and measurements. All Simulations are performed by using CST Studio Microwave Suite® program and measurements are performed in an anechoic chamber using a network analyzer. Results: The first resonance frequency for the 1st and 2nd feeding points in the rectangular heatsink is 3 GHz and the reflection coefficient values at this frequency are -10.1 dB and -12.3 dB, respectively. In the circular heatsink, the first resonance frequency for the 3rd and 4th feeding points is 2.2 GHz and reflection coefficient values at this frequency are -14.9 dB and -17.3 dB, respectively. In rectangular heatsinks, the emission for the 1st and 2nd feeding points in the 1-2 GHz and 6-10 GHz frequency bands should be preferred since it is ~5-6 dBmV/m less than others in Figure A. Conclusion: When the operating frequency of the components around the heatsink is the same as the resonance frequency of the heatsink, the form of component placement that constitutes the respective feeding point should not be preferred. The resonance frequency can be shifted by changing the feeding point.