Design and development of field emission based magnetron for industrial applications using conformal finite-difference time-domain particle-in-cell simulations

The magnetron is a high-efficiency high-power vacuum tube that generates microwaves based on the interaction of a stream of moving electrons under crossed electric and magnetic fields with a series of open coupled cavity resonators. They are widely used as a low-cost microwave source for industrial heating. Traditionally, a thermionic cathode is used as the electron source and a heater is needed to increase the temperature of the cathode up to about 1000 K. In this work, a field emission-based magnetron has been investigated for industrial applications as an easier and more robust configuration. The design and development were performed using a conformal finite-difference time-domain particle-in-cell simulation as implemented in the VSim code. A rising-sun configuration has been optimized and the corresponding operating condition has been determined to achieve an efficiency of up to ∼80%. The rising-sun magnetron operating at a frequency of 2.45 GHz can give an output power of 3 kW, serving as a good replacement of existing industrial magnetrons.