Experimental Study of Millimeter Magnetrons With Cold Cathodes

The cold cathode magnetron is one of the most significant research areas in the development of magnetrons. Unlike the thermionic cathode magnetron, such a device is capable to start up instantaneously, while featuring an excellent stability and reliability as compared with the thermionic one. In this paper, we report on the cold start-up performance of four types of cold cathode magnetrons, i.e., barium-tungsten (Ba-W), Ba-W priming, Pd-Ba alloy, and diamond coated cathodes. Based on the measured data, the Pd-Ba (3.5% in weight) alloy cathode was found to be the best for the magnetron. This magnetron was able to start up instantly without using extra filaments, with a start-up time of less than 5 s. At the same time, its output characteristics, such as pulsewidth and output power, are comparable to the same structural magnetron with conventional thermionic cathodes.