Design and Development of Field Emission Based Magnetron for Industrial Applications Using Cfdtd Pic Simulations
Ling Li, Kaviya Aranganadin, and Ming-Chieh Lin1*
1Multidisciplinary Computational Laboratory, Department of Electrical and Biomedical Engineering, Hanyang University, Seoul, Korea
* Presenter:Ling Li, Kaviya Aranganadin, and Ming-Chieh Lin
Magnetron is a high-power vacuum tube that generates microwaves based on the interaction of a stream of moving electrons under a cross electric and magnetic fields with a series of open coupled metal cavity resonators. The magnetron is widely used in radars and also well-known as a low-cost microwave source for microwave ovens. 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 proposed and investigated for industrial applications. The corresponding design and development utilize the state of the art conformal finite-difference time-domain (CFDTD) particle-in-cell (PIC) simulation. With the use of a field emission cathode to replace a thermionic one, not only the lifetime can be extended but the complexity of the external circuit and assembly process can be much reduced. In addition, in order to further ease the fabrication and reliability, a rising sun configuration is chosen instead of a trapped conventional magnetron. A 2-D CFDTD PIC simulation can be used due to the axial symmetry and a 10-vane field emission based rising sun magnetron has been built and simulated in the VSim code. It is demonstrated that a preliminary design after the optimization of an operating point would give a higher output power and achieve a high efficiency of above 60%. Based on the rising sun configuration, a 2.45 GHz >100 kW field emission based magnetron is feasible, according to the achievable current density from widely available FEAs. The fabrication and assembly can be much simplified compared with a conventional strapped magnetron with a thermionic cathode.

Keywords: magnetron, field emission, CFDTD, PIC