MATERIALS CHEMISTRY AND PHYSICS, cilt.1, ss.1-10, 2024 (SCI-Expanded)
Metal foams or cellular structures like honeycombs, can also be
evaluated according to mechanical, acoustic, thermal, and chemical
resistance parameters in terms of functionality. However, it is vital to
investigate the performance of these cellular structures' radiated
emission (RE), which can be used as PCB heatsinks. In this study, the
radiated emission (RE) performance of honeycomb-structured aluminum foam
(or cellular) heatsinks (AFH), which can be considered as
unidirectional regular foam, is examined in the frequency range of 1-10
GHz as a novelty. Also, the effect of four primary variables (the
geometry of AFH, honeycomb hole direction, honeycomb cell size, and
honeycomb cell wall thickness) on the RE performance of AFH is
investigated. Unlike classical honeycomb production methods, the
investment flask mold casting (loss wax) method is preferred due to the
complex offset strip geometry of designed honeycombs. The original
design offset hexagonal honeycomb structures were successfully produced
using this investment casting method with additive manufacturing
technologies from molten metal. While all simulations are carried out
using CST Studio Suite, the RE performance of the proposed AFHs is
measured in a standard 3 m fully anechoic chamber using a reference horn
antenna and vector network analyzer (VNA). When the results are
examined, the measured and simulated results agree with each other
quietly. Regarding RE, structures with a CPI value of 14 are better at
low frequencies, while structures with a CPI value of 3.5 are better at
high frequencies. Secondly, the honeycomb cell thickness value does not
significantly affect EMI performance. Lastly, although there is no
significant difference in EMI in the low-frequency region, it is better
to use a directional structure with vertical holes in the high-frequency
region. As a result, in the design of AFH, the RE performances of the
heatsinks and their thermal performance should be considered.