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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 ...
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.
This was developed by John Randall (1905-1984) and Harry Boot (1917-1983) at Birmingham University. Radars that could produce clear images of distant objects played a decisive role in World War II, by bouncing powerful, ultra-short radio waves off their targets. The cavity magnetron was the first practical device for producing such waves.
A microwave cavity or radio frequency cavity (RF cavity) is a special type of resonator, consisting of a closed (or largely closed) metal structure that confines electromagnetic fields in the microwave or RF region of the spectrum. The structure is either hollow or filled with dielectric material. The microwaves bounce back and forth between ...
English: Diagram of a resonant cavity magnetron in SVG adapted from a PNG image by Ian Dunster 14:04, 14 November 2005 (UTC) from a diagram in Radar by T. J. Morgan - part of the The Mechanical Age Library - Muller - c1950 - No ISBN
The anode block of the original cavity magnetron built by Randal and Boot, which provided a leap forward in radar design The history of radar (where radar stands for radio detection and ranging ) started with experiments by Heinrich Hertz in the late 19th century that showed that radio waves were reflected by metallic objects.
The introduction of the cavity magnetron from Britain to the United States in 1940 during the Tizard Mission resulted in a pressing need for a practical high-frequency amplifier. [citation needed] On a whim, Russell Ohl of Bell Laboratories decided to try a cat's whisker. By this point, they had not been in use for a number of years, and no one ...
The introduction of phase-coherent klystron transmitters, as opposed to the incoherent cavity magnetron used on earlier radars, led to the introduction of a new MTI technique. In these systems, the signal was not fed directly to the display, but first fed into a phase detector. Stationary objects did not change the phase from pulse to pulse ...