A Power Combination System Based on Phase-Shifterless Scheme for Four Injection Locked S-Band Magnetrons

Efforts to conceive high-efficiency high power microwave (HPM) sources has lately been the research focus due to significant demands in industrial and military applications. Magnetrons have emerged as promising high-efficiency HPM oscillators. The output power of a continuous wave (CW) magnetron is currently limited to kilowatt levels. To meet increased industrial demands, various schemes have been widely implemented to combine the power of multiple magnetrons through injection locking. A new approach to power combining four magnetons is proposed in this article, which does not employ phase shifters and high insertion-loss ferrite circulators in the high-power paths. The proposed combiner is based on two asymmetric Magic Tees, each first individually combining the power of two magnetrons, then a symmetric magic tee (SMT) is used down the chain to combine the signals of all four magnetrons. Additional waveguide extensions are also used for phase-matching, and a combining efficiency of 93% is achieved.