Microwave ovens use microwaves to heat food. Microwave is an electromagnetic wave with very short wavelength, which is composed of alternating electric and magnetic fields. Microwave has much more energy than ordinary radio waves. When encountering objects in the process of microwave propagation, they will be reflected, transmitted or absorbed to varying degrees according to the different materials of the objects. The microwave oven is mainly composed of magnetron, antenna, waveguide, agitator and box. The magnetron uses electric energy to generate microwave, which is emitted from the end of the antenna and transmitted to the microwave mountain pass on the upper wall of the microwave oven through a hollow waveguide. At the exit, a stirrer shaped like a fan blade disperses the microwave. A part of the microwave emitted directly hits the food, and a part of the microwave is reflected to the food through the inner wall of the microwave oven, so that the food can receive more uniform microwave irradiation from all aspects.