The cavity magnetron is a vacuum tube that generates microwaves using magnetic fields to manipulate streams of electrons. It was developed in 1940 and enabled the development of portable radar units. It is still used in radar equipment and microwave ovens, although newer technologies are starting to displace it in some applications.
A cavity magnetron is a type of vacuum tube that generates microwaves, which are short wavelength radio waves. The streams of electrons are manipulated by magnetic fields, causing the emission of microwaves. The first cavity magnetron was developed by two British physicists in 1940 and led to the development of portable radar units. Today these devices are still used in radar equipment and as a generator of the electromagnetic waves that every microwave oven uses to cook food.
A cathode is mounted in the center of an anode in the shape of a hollow cylinder. The central cavity, also in the shape of a cylinder, is connected to further smaller cavities in the outer wall of the cylinder and a large magnet is mounted at either end. Magnetic fields cause electrons to spiral around the cathode as they travel towards the anode instead of moving in straight lines. The interaction of the electron flow with the magnetic field causes an electrical resonance field within the cavities of the outer wall of the cylinder, which emits microwaves. A cavity magnetron can be designed to emit microwaves of a desired frequency.
The development of the cavity magnetron was one of the most important technological advances in the 20th century. Its implementation made it possible to mount portable radar units on ships and airplanes, as well as making land-based radars much more efficient and effective. This improved radar technology is widely credited with giving the Allies a significant advantage over the Axis powers in this area during WWII.
As of 2011, cavity magnetrons are still widely used for radar systems, although new technologies using alternative transmitters are starting to displace them. This is due to the fact that the very nature of the oscillating electric fields that microwaves emit makes it difficult to tune them to precise narrow frequency bands, as well as other considerations, such as human proximity to powerful electromagnetic radiation when these systems are mounted on aircraft and military ships. Existing radar systems are generally not replaced or upgraded, and for this reason cavity magnetrons will continue to see service in radar equipment for many years or even decades.
Microwave ovens use cavity magnetrons, although much smaller and less powerful than those used for radar equipment. In a microwave oven, the microwaves are directed into the cooking box and are distributed by a diffuser, which helps foods cook more evenly. Most microwave ovens use a cavity magnetron that outputs a maximum of about 2500 watts in large commercial models, while very powerful cavity magnetrons used for radar applications can produce millions of watts.
Protect your devices with Threat Protection by NordVPN
