A novel passive cooling heat sink for thermal regulation of concentrated photovoltaics (CPV) and its performance improvement based on phase change material (PCM) embedded in the metal foam has been introduced in this study. Eighteen different patterns have been considered for the heat sink to investigate the influence of series/parallel porosity gradient arrangement, foam material gradient, inclination angle, and pore density. A computational fluid dynamics simulation has been developed to analyze the transient heat charging mechanism and evaluate the effects of porosity/material gradient with different arrangements on the conduction/convection heat transfer processes in the foam-PCM-CPV. The results revealed that parallel positive porosity gradient in y-direction could enhance the natural convection and the conduction heat transfer compared to the series negative porosity gradient in the xdirection and reduce the time-average CPV temperature by 6.76 C and enhance the time-average electrical efficiency by 3.93%. The results also indicated that using an obtuse inclination angle instead of anacute one may reduce the CPV temperature by about 5 C and leads to an electrical efficiency improvement of 2.65%. The lower value of pore density is another determinative factor that could enhance the total absorbed heat by about 12% for different patterns.