The inside of a magnetron removed from a microwave oven. The magnetron is a device that creates microwave radiation. A magnetron consists of an electron tube surrounded by a magnet. As electrons are released from the heated cathode they are forced to take a spiral path to the anode by the magnetic field, creating microwaves. This magnetron creates a microwave radiation that is the same frequency as a water molecule vibrates. When water is exposed to just the right frequency, the water molecules will gain kinetic energy and become hotter.