High-Efficiency Phase-Locking of Millimeter-Wave Magnetron for High-Power Array Applications

We introduced a phase-locking mechanism of millimeter-wave magnetrons coupled through a carefully designed coupling bridge. For such a structure, two Ka-band 22-vane rising-sun magnetron circuits operated in the \pi -mode were phase-locked tightly as a whole through a double-ridged coupler. Moreover, the double-ridged coupler was optimized to suppress mode competition between zero-phase and \pi -phase difference mode, which achieved high-efficiency phase-locking. Total output power of the two identical magnetrons nearly doubled the output power of a free-running magnetron and efficiencies of them were nearly the same. Extension of this phase-locking mechanism to high-power applications appears feasible with more elements in an array of the millimeter-wave magnetrons.