Abstract: The development of high power and integration of active phased array antenna leads to increase of the heat flux of the key functional unit T/R module and further causes the temperature drift of the internal thermal element and the electrical performance deterioration of the antenna. In this paper, the structural innovation of the conventional cooling plate is carried out. Based on the embedded ideology and combined with the microchannel optimization strategy of local densification, a quadrangular pyramid-shaped micro-rib array structure is designed for the high heat flow and localized hotspot problem. Simulations reveal that denser micro-rib configurations reduce the maximum temperature of the device by 22.58 K and improve temperature uniformity by 22.5% under high-power conditions. When the micro-ribs array is placed far from heat sources, embedded cooling performance will be improved. While the micro-ribs array is placed near heat sources, embedded cooling performance will be further improved, but it will make the whole layout design and packaging of the electronic devices more difficult. These results provide theoretical insights for solving embedded cooling problem in high-power electronics like T/R modules.