Abstract: Ultra-wideband solid-state power amplifier has a mutually constraining relationship in high-power synthesis, high-heat flux dissipation and lightweight miniaturization. Based on the ridge waveguide H-plane T-type power division/synthesis and wave impedance transformation topological architecture, this design achieves ultra-wideband (6 GHz~18 GHz) 4-way 12 W (typical value) waveguide synthesis output ≥ 40 W, synthesis efficiency ≥ 90%, and takes the standard waveguide port WRD500D36 as the radio frequency end face, which is convenient for the secondary efficient synthesis of the system. An aluminum-embedded copper process is adopted by the structure and the copper is partially buried beneath the high heat source, which can reduce the weight of the power amplifier chip by 54.5% compared to pure copper while meeting the requirements of high heat flux heat dissipation. The vertical interconnection technology is adopted for power supply system. The inherent three-dimensional structure space of waveguides is utilized, and power supply spring pins are employed to achieve vertical interconnection between the power supply board and the chip power supply. This approach simplifies the assembly process and further realizes weight reduction and optimized utilization of structural space. Finally, the high integration of high power, high heat flux heat dissipation, and lightweight miniaturization of the structure is realized, providing the core basic module for the development of solid-state amplifiers with higher power in the 6 GHz~18 GHz.