Phase Control Demonstration of <i>S</i>-Band Hybrid Phase-Locking Magnetrons for Array Applications

To meet the phase control requirements of magnetrons in large-scale array applications, the advantages of injection locking and cascaded mutual coupling phase locking are fully integrated. A hybrid phase-locking system for magnetrons is proposed. By performing external injection on just one magnetron within the cascaded mutual coupling structure, simultaneous frequency locking of both magnetrons can be achieved. Simulation and experimental results indicate that two phase-locking regions emerge during one period of phase variation. By quantifying the power flow across the four ports of the phase locker, it is determined that the power necessary for phase locking is less than 1% of the total output power. External frequency tuning enables the stabilization of the frequencies of both magnetrons, resulting in a purer spectrum. With an injection ratio of −18.97 dB, the mutual coupling phase locker can be adjusted to vary the phase difference between the output signals of the two magnetrons within the range from −126° to 171°. This facilitates phase control of the output signals from the two magnetrons. The phase-locking efficiency of this system is 88.2%. The hybrid phase-locking approach achieves high-efficiency phase locking and power output. This approach is particularly suited for coherent power synthesis and phase scanning in large-scale array applications.