Microwave Oven Grille is often added to the door of the microwave oven, which is a shielding mesh to prevent microwave leakage. Microwave is a kind of electromagnetic wave, too strong electromagnetic wave will cause harm to people, so microwave oven needs to use a metal case to shield the electromagnetic wave in the case. The microwave oven door needs to observe the heating of the food and block the electromagnetic radiation. After calculation and testing, the structure of the microwave oven door and the metal mesh structure can play the role of shielding electromagnetic waves, and can observe the food and heating inside. As long as the size of the metal mesh grid is much smaller than the wavelength of the microwave, it can effectively shield the influence of electromagnetic waves on the outside world.