This work introduces an enlarged mini-channel baseplate using a porous pin-fin with mesh surface (PPMMS) structure, doubling the channel length from 44 mm to 88 mm on a 124 × 53 mm copper plate to align with commercial SiC/GaN module dimensions. Conventional mini-channels struggle beyond 50 mm due to oscillations, dryout, and pressure drops, but the PPMMS design sustains capillary rewetting, promotes earlier nucleate boiling, and improves vapor venting. Compared with the 44 mm baseline, the extended plate dissipated 489 W (50.3%) more heat before reaching 150 °C and lowered thermal resistance by 30.4%. High-speed imaging confirmed stable boiling regimes, while simple geometric modifications (porous, pin-fin, mesh) provide scalable design rules for practical two-phase cooling.
