A Multiphysics Approach To Magnetron And Microwave Oven DesignSource: CST of America, Inc.
The magnetrons used in microwave ovens operate on the same frequency band as Wi-Fi equipment, and the radiation they release can interfere with the operation of wireless networks. This paper presents a multiphysics simulation of a magnetron using CST STUDIO SUITE®, with the aim of testing the electrical, magnetic, thermal and mechanical characteristics of a low-interference magnetron design. The simulation results are then compared to measurements made experimentally, and the two sets of results are shown to be in good agreement.
Magnetrons are widely used as RF power sources because they offer high energy conversion efficiency (around 75%) at a low cost. The magnetron was invented during World War II, when its small size, high power and short wavelength made it ideal for use in radar, but with mass production and the development of automatic manufacturing techniques, magnetrons made the move into the home as the radiation source in microwave ovens.
The problem with the microwave oven’s widespread adoption is that magnetrons generate significant amounts of RF noise; the ones used in ovens radiate at around 2.45 GHz. Historically this frequency band was reserved for noisy industrial applications, and little consideration was given to the risk of electromagnetic interference (EMI), but the rise of short-range wireless communication systems such as Wi-Fi and Bluetooth operating on the same frequencies means the microwave oven is now a major potential source of interference to computer networks and mobile communications.