Metal 3-D Stacking-Enabled WR4.3-Band Power Amplifier Featuring High-Power-Density TM01-Mode Radial Power Combiner

This letter reports a novel WR-4.3 band solid-state radial power combiner featuring high power density. It integrates a TE₁₀–TM₀₁-mode transducer, eight reconfigurable compact two-channel combined power amplifier (PA) units, and a highly efficient eight-channel radial power combined network to enable a 16-channel terahertz (THz) monolithic integrated circuits (TMICSs) combined amplifier. Experimental results demonstrate a saturated output power of over 400 mW at around 220 GHz, with a peak output power of 436 mW achieved at 215.4 GHz, corresponding to a maximum active combining efficiency of 89%. Additionally, the radial power combiner exhibits an ultracompact form factor, with a total volume of only 30.4 cm², resulting in a maximum functional power density exceeding 14.35 mW/cm². This work highlights the potential of the proposed architecture for high-power THz applications requiring compact and efficient power-combining solutions.