Design and development of field emission based magnetron for industrial applications using CFDTD PIC simulations

Abstract

Magnetron is a high-efficiency and high-power vacuum tube that generates microwaves based on the interaction of a stream of moving electrons under crossed electric and magnetic fields within a series of open coupled cavity resonators. The magnetron is 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 1,000 K. In this work, a field emission based magnetron is investigated for industrial applications as an easier configuration and longer lifetime can be expected. The design and development are 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 up to ~80%. The field emission based 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.