Search results
Results From The WOW.Com Content Network
The cavity magnetron is a high-power vacuum tube used in early radar systems and subsequently in microwave ovens and in linear particle accelerators. A cavity magnetron generates microwaves using the interaction of a stream of electrons with a magnetic field , while moving past a series of cavity resonators , which are small, open cavities in a ...
Electrically, this is similar to the two cavity oscillator klystron with considerable feedback between the two cavities. Electrons exiting the source cavity are velocity modulated by the electric field as they travel through the drift tube and emerge at the destination chamber in bunches, delivering power to the oscillation in the cavity.
FuG 224 Berlin A, and the contemporary FuG 240 Berlin N1 or Nachtjagd air interception radar, [1] [2] both made use of captured examples of the British cavity magnetron in the H2S radar. A H2S-equipped Short Stirling bomber had crashed near Rotterdam on the night of 2 February 1943. [3] This led to H2S being given the German codename Rotterdam ...
However, the introduction of the cavity magnetron in 1940 changed things dramatically. The magnetron efficiently generated microwaves from a device the size of a coffee tin, lowering operational wavelengths from the several-meter range to less than 10 centimeters. This reduced the antenna size to a few centimeters.
Sir John Turton Randall, FRS FRSE [2] (23 March 1905 – 16 June 1984) was an English physicist and biophysicist, credited with radical improvement of the cavity magnetron, an essential component of centimetric wavelength radar, which was one of the keys to the Allied victory in the Second World War.
He was the leader of a group working on the cavity magnetron from April 1940 in north-west London. [7] The cavity magnetron was producing power of around 500W (E1188 version). Eric Megaw changed the design, coating the cathode with oxides (E1189 version) [ 8 ] and eight segments from six, to increase the power to 100 kW by September 1940 ...
The resonant cavity magnetron continued to evolve at the Rad Lab. A team led by I.I. Rabi first extended the operation of the magnetron from 10-cm (called S-band), to 6-cm (C-band), then to 3-cm (X-band), and eventually to 1-cm (K-band). To keep pace, all of the other radar sub-systems also were evolving continuously.
In 1940, John Randall and Harry Boot, PhD students at the University of Birmingham, devised a new microwave-frequency vacuum tube known as the cavity magnetron that output thousands of watts of radio signal at 9 cm wavelength. At this wavelength, the antennas were only a few centimeters long, making radar much easier to fit into an aircraft.