Quarter Wavelength Combiner For An 8.5kw Solid State Amplifier And Conceptual Study Of Hybrid Combiners

Experimental results to combine ten 900W solid state amplifier modules based on typical quarter wavelength 10-way combiners are described for a total of 8.5kW RF power output at 500 MHz. The power gain and phase distribution among the ten modules are measured and calculated to sense the combination efficiency. The combination efficiency of 100 modules differing in power gain and phase distribution is theoretically analysed. Groups of 5, 10, 25, 50 and 100 units are used in 4, 3, 2, and 1-stage power combination for total 100 units and the characteristics are calculated and investigated, including bandwidth, efficiency and even redundancy under various output VSWR levels. To simplify combining complexity and to eliminate the drawbacks of single stage combiners, a multi way 2-stage coaxial to waveguide combiner is thus proposed as an expandable power combiner.