All books are in the public domain and are free for reuse and. This means lower cathode emission density, lower life and higher reliability. Click here to go to our new page on the history of ther microwave oven the magnetron is the tube was what enabled airborne radar at microwave frequencies during wwii. A magnetron uses this direct current and generates microwaves with a frequency of 2450 megacyles per second or 2. The physical construction of a vacuum tube causes the output power and available gain to decrease with increasing frequency. The first chapter of this book contains general information concerning the work and responsibilities of the builder, a brief discussion of his place in the construction battalion and naval organization, and reference to a valuable supply of source material. Title is somewhat cryptic concise, notablyexcellent article about magnetrons. Its working principle is based on the interaction between electron stream and magnetic field. The original amana radarange and other early microwave ovens. Microwave ovens, all about the magnetron, the educational. You need to provide only a few basic contact details and a brief profile to become an eemua registered user.
Magnetic lines of force are parallel to the geometric axis of this structure. They contain a wide variety of technical information, and date back as far as world war ii. Cwm10s microdry incorporated 5901 west highway 22 crestwood ky, 40014 ph. Closeup view of magnetron with buckboost coil fitted to waveguide in phase and amplitude tracking test bed. As well as regular events throughout the year, eemua provides a wide range of publications, elearning and classroombased training and competency courses on the key topics affecting industrial plant. Magnetron sputtering an overview sciencedirect topics.
Microwave magnetrons radiation laboratory series 6 describes in great detail the development of the microwave magnetron during ww 2. May 23, 20 first magnetron tube was invented in 1940 at englands university by john randall and harry boot. The structure of this thesis follows the above discussed approach. Highly efficient water heaters using magnetron effects. The heated cathode at one end of the tube produces a beam of electrons and is attracted to the collector at the other end of the tube. Design aspects of rotating cylindrical magnetron cathode. In turn, this fan points the waves into the oven cavity where they heat the food inside. What is the magnetron efficiency in microwaves and how it. Lawrence in 19291930 at the university of california, berkeley, and patented in 1932. Magnetron construction basic textbook description this is the description you will find in any textbook on radar or microwave engineering. It is amazing the technology that was accomplished back in the early 40s without the aid of computers that we take for granted today humbles me.
The microwaves are directed by an antenna at the top of the magnetron into a waveguide. A thick cylindrical cathode is present at the center and a cylindrical block of copper, is fixed axially, which acts as an anode. Their lowimpedance design provide rf, dc, mid frequency dc, pulse dc, and microwave power compatibility. Electrons pass by the openings to these cavities and cause microwaves to oscillate within, similar to the way a whistle produces a tone when excited by an air stream blown past its. Korobeinikov offered magnetron effects for heating, it was published in new energy technologies 2, 2005. This paper describes the fabrication of high power sband tunable pulse magnetron capable of delivering peak and average powers of 3. Industrial magnetrons toshiba hokuto electronics corporation. Magnetron construction angstrom science solid construction. Though there are several designs presently in use, large scope exists for improvements in the design of cylindrical magnetron cathodes. We also acknowledge previous national science foundation support under grant numbers 1246120, 1525057, and 14739. In return youll receive personalised content, access to webinar recordings and your own my eemua page that brings together information about news, publications, events and courses of interest to you.
Magnetron tubes are representative of an entirely different kind of tube than the iot and klystron. Magnetron high power system design article pdf available in international journal of simulation. Travelling wave tube twt the twt, because of its construction and working principle has enormous bandwidths and low noise. Magnetron physical construction of a magnetron, magnetrons function as selfexcited microwave oscillators. Design, construction, and optimization of a magnetron. It consists of anode and cathode poles and a permanent magnet. The waveguide channels microwaves to a fanlike device called a stirrer which disperses them inside the oven cavity. Us4842703a magnetron cathode and method for sputter coating. The filament and anode body are packed into a single device together with permanent magnets and, is some cases, additional electromagnetic coils, which permit to control and vary the output power of the magnetron.
By careful design, the magnet can spin the electrons around the gap in the magnetron, when the force the magnet exerts is equal to the centrifugal force of the spinning electrons. Crossed electron and magnetic fields are used in the magnetron to produce the highpower output required in radar equipment. This is a collection of navy training courses developed by the u. Each cavity works like a parallel resonant circuit. As shown in the given diagram the circular waveguide is designed from a conducting pipe which is hollow from the center and polished from interior portion.
Whereas the latter tubes use a linear electron beam, the magnetron directs its electron beam in a circular pattern by means of a strong magnetic field. They invented a valve that could produce multi kilowatt pulses at 10 cm wavelength, an unprecedented achievement. The cavity magnetron was radically improved by john randall and harry boot at the university of birmingham, england in 1940. The assembly includes a concave consumable target spaced closely to a substrate coating position. He describes how the microwave vacuum tube, called a magnetron, generates radio frequencies that cause the water in food to rotate back and forth. The effect is that the magnet defects the electrons sideways. The particles are held to a spiral trajectory by a static magnetic field and accelerated by a rapidly varying radio frequency electric field. As depicted in figure 3 by the low frequency analogue, the rear wall of the structure of the anode bloc may be. Table 1 gives an overview of the most important compound films.
Free checklists and guidance are available to download on this website. A magnetron consists of a filament in the centre of the tube, acting as the cathode, with the anode body surrounding the filament. Numerical studies and optimization of magnetron with diffraction. Another difference you will notice is that the 2j51 magnetron uses. The high power of pulses from the device made centimeterband radar practical for the allies of world war. This research project has several stages of development.
Coating uniformity is maintained by controlling ion formation between the substrate and the target. Why magnetrons fail 1 why magnetrons fail understanding points of breakdown for these key components is crucial to maintaining roi no component is more critical to an industrial microwave system than the magnetron, and none is more complex and, therefore, subject to failure from a variety of causes. Advantages the magnetron is a fairly efficient device. The cavity magnetron is a highpowered vacuum tube that generates microwaves using the. Click here to go to our main page on microwave tubes. The cavity magnetron is a highpowered vacuum tube that generates microwaves using the interaction of a stream of electrons with a magnetic field while moving past a series of open metal cavities cavity resonators. Modification of microwave oven magnetron showing 1 magnetron stripped of cooling fins and ceramic magnets 2buckboost coil,3coldrolled steel shell,and 4 samarium cobalt magnets insideends of each portion of shell. The outer surface of the wave guide is coded with the insulated paint in order to avoid dust and rust. Cavity magnetron depend upon the interaction of electrons with a rotating electromagnetic eld of constant angular velocity. However, many applications in various industrial fields also need oxides, nitrides, or carbides. The combination of the smallcavity magnetron, small antennas, and high resolution allowed small, high quality radars to be installed in aircraft. Component parts of the raytheon 5126 magnetron designed for microwave applications see p 118. Satellite power system sps magnetron tube assessment study. Magnetrons the heart of every microwave oven is the high voltage system.
Magnetron magnetron as high efficient heater, pdf file. The anode has several cavities that open into interaction space. Westwood, sputter deposition, avs education committee book. First magnetron tube was invented in 1940 at englands university by john randall and harry boot. A magnetron is a microwave oscillator that consists of a diode and a.
Each angstrom sciences magnetron is machined from solid 304 stainless steel, aircraft grade 6061 aluminum and ofhc copper, ensuring magnetic and electrical integrity for longterm, reliable operation. Never operate the magnetron unless it is properly installed. Navy through the bureau of naval personnel navpers for short. Robust mechanical and electrical construction corrosion resistant and modular magnet bars optimized magnetics to maximize bulk target erosion and deposited film uniformity profiled magnetics to reduce the separation distance between adjacent racetracks. In a completed microwave oven, the magnetron tube creates the microwaves, and the waveguide directs them to the stirrer fan. Continuous wave magnetrons are used for plasma processing in the manufacture of semiconductors and in industrial dielectric heating applications. He describes how the microwave vacuum tube, called a magnetron, generates radio frequencies that cause the. Satellite power system sps magnetron tube assessment. Magnetron sputtering is a highrate vacuum coating technique that allows the deposition of many types of materials, including metals and ceramics, onto as many types of substrate materials by the use of a specially formed magnetic field applied to a diode sputtering target. Review of the relativistic magnetron by dmitrii andreev, artem kuskov, and edl schamiloglu.
The magnetron is a vacuum tube which is used in the generation of microwaves of high power. Robust mechanical and electrical construction corrosion resistant and modular magnet bars optimized magnetics to maximize bulk target erosion and deposited film uniformity profiled magnetics to reduce the separation distance between adjacent racetracks vapor phase efficiency. Velocitymodulated tubes this educational endowment is a printable summary of all topics about velocity modulates tubes of the internet representation radar basics on. Magnetron cavity is used in radar and microwave ovens. Hence in the present book, design aspects of cylindrical magnetron cathodes useful for coating inner or outer surfaces of planar or tubular surfaces were discussed and arrived at improved performance r c. Slater abstract the main problems considered in this paper are the phase locking of a magnetron with a small external signal whobe frequency is nearly the natural frequency of the magnetron, and the locking together of two or more magnetrons. The magnetron tube works on dc direct current power. If the apparatus has been stored at a temperature within the allowed storage range but outside the allowed operating range, it must be kept at an ambient temperature, within the allowed operating range, for at least 2 hours prior to turning the apparatus on. Click here to go to our main page on microwave amplifiers. We have 2 sharp r1880lst manuals available for free pdf download.
Many companies have joined us as corporate or associate members. Whereas all stored energy in a conventional is confined to the. Pdf it is a common belief by many people that the resonantcavity magnetron was invented in february 1940. This is not as simple question to answer because magnetrons do not operate in isolation so their efficiency varies greatly depending upon how well the magnetron is matched to the load. A cyclotron is a type of particle accelerator invented by ernest o. Pdf format this is an excellent, concise account of how magnetrons developed around the time of world war ii in the united states, the uk, and canada. How microwave oven is made manufacture, making, used, parts. So what you have is a gas of electrons, spinning like a tornado around and around inside the magnetron. Notes on the troubleshooting and repair of microwave ovens. Cavity magnetron microwave manufactured goods free. Angstrom sciences has developed cylindrical magnetron technology that embody. The em magnetron method apparatus provide accurate results when the following conditions are met it is within its calibration cycle. Topics include basic microwave theory as well as a complete discussion of microwave oven magnetron construction and principles of operation. Highly efficient water heaters using magnetron effects technical task of this project is maximum heat output and minimum electric input of power.
The space between cathode and anode is called interaction space. The minimum operating pressure of every magnetron is given by its construction design and particularly by 1 the magnitude of b par on the surface of sputtered target, 2 the distribution of magnetic field b lines on sputtered target and eventually 3 the additional means, such as additional eb, rf or microwave discharges fig. Sharp r1880lst manuals manuals and user guides for sharp r1880lst. Jun 26, 2012 bill details how a microwave oven heats food. Magnetron mi 29g 29 of the old russian radar bar lock the magnetron is a highpowered vacuum tube, that works as selfexcited microwave oscillator. Magnetron sputtering of metals is not a big challenge if the target surface is clean and proper process conditions base pressure, process pressure, and power are applied. In a magnetron, the source of electrons is a heated cathode located on the axis of an anode structure containing a number of microwave resonators. Unlike other appliances, the microwave oven is highvoltage and highcurrent equipment. A cyclotron accelerates charged particles outwards from the center along a spiral path.
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