Abstract:This paper innovatively proposed thin vapor chambers based on gradient porosity copper foam/copper mesh composite structure to meet heat dissipation requirements of 5G communication equipment with high power density. Through two-way pore gradient design, thickness of copper foam was compressed from 1.6 mm to 0.15 mm by hot pressing technology at the evaporation end, forming a high-density microporous structure to enhance capillary. The condensation end was configured with 150 μm pore copper mesh to optimize the working medium reflux path, significantly reducing flow resistance. Experimental results showed that the design can reduce temperature fluctuation from 10.3 ℃ to 5.2 ℃ (a decrease of 49%) under a heat load of 65 W, with a thermal resistance (ΔRth) of only 0.08 ℃/W. In particular, the gradient structure shortened start-up time to 8 s, providing a new idea for heat dissipation of miniaturized electronic devices. This study provided a new paradigm for the miniaturization and heat dissipation of high-power electronic devices, balancing efficient heat transfer and structural reliability. Design concept of the three-stage flow channel (large hole for evaporation end → middle hole for transition layer → small hole for copper mesh) can be extended to other high heat density application scenarios.