Design and operation of a module of phase-locked relativistic magnetrons

We have achieved phase‐locked operation of a module consisting of up to seven relativistic magnetrons. The magnetrons are connected by waveguide in a peer/peer configuration, with no one magnetron acting as a master oscillator. The signals used for coupling are each a substantial fraction of a magnetron’s radiated power. Total extracted power, at 2.8 GHz, was 2.0 GW with four magnetrons and 2.9 GW with seven. Several interconnection geometries were explored. One particular geometry was found to produce qualitatively better phase‐locked operation than any other. This was in agreement with the predictions of a numerical model of the magnetrons as coupled van der Pol oscillators.