Peer-peer phase-locking of two L-band industrial heating magnetrons

Abstract

We demonstrate the peer-peer phase-locked operation of two matched industrial heating magnetrons. Two commercial off-the-shelf California Tube Laboratory model CWM-75L industrial heating magnetrons were "cherry picked" for identical operating voltage (17.5 kV), current (5.0 A), operating frequency (915 MHz), and output power (75 kW). Their microwave power outputs were cross-coupled by means of a four-port branch wall directional coupler and phase shifter. Coupling as low as -20 dB of each other's output powers was sufficient to create mutual locked operation between both magnetrons. These results suggest more than two matched magnetrons may be driven in a phased-locked condition.