Microwave Sources

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<h1>Microwave Sources</h1><strong> Author: <a href='http://www.articleseen.com/profile_Johnny Diaz.aspx'>Johnny Diaz</a></strong><br /><p>High power microwave sources use specialized vacuum tube to generate microwaves. In electronics, a vacuum tube, also referred as electron tube in North America, and thermionic valve elsewhere, especially in Britain, reduced to simply “tube” or “valve” in everyday parlance, is a device that relies on the flow of electric current through a vacuum. These devices operate on different principles from low-frequency vacuum tubes, using the ballistic motion of electrons in a vacuum under the influence of controlling electric or magnetic fields, and include: the cavity magnetron, a high-powered vacuum tube that generates microwaves using the interaction of a stream of electrons with a magnetic field, (used in microwave ovens, which is often referred as simply “microwave,” a kitchen appliance that heats food by dielectric heating, using microwave radiation to excite polarized molecules within the food); klystron, a specialized linear-beam vacuum tube (evacuated electron tube); traveling-wave tube (TWT), an electronic device used to amplify radio frequency (RF) signals to high power which is usually in an electronic assembly known as a travelling-wave tube amplifier (TWTA); and gyroton, a high-powered vacuum tube which emit millimeter-wave beams by bunching electrons with cyclotron motion in a strong magnetic field. These devices work in the density (m/v) modulated mode, rather than the current (electric charge) modulated mode, which means that they work on the basis of clumps of electrons flying violently through them, rather than using a continuous stream of electrons. Low-power microwave sources use solid-state devices like: the field-effect transistor (at least, at lower frequencies), a transistor relying on an electric field to control the shape, hence, the productivity of a channel of one type of charge carrier in a semiconductor material; tunnel diode, or Esaki diode, a type of semiconductor diode capable of very fast operation into the microwave frequency region by using quantum mechanical effects; Gunn diodes, also known as a transferred electron device (TED), a form of diode used in high-frequency electronics, and IMPATT (IMpact ionization Avalanche Transit-Time) diodes, a form of high-power diode used in high-frequency electronics and microwave devices. A maser is a device that produces coherent electromagnetic waves through amplification by stimulated emission, similar to laser which is a device that emits light (electromagnetic radiation) through a process of optical amplification based on the stimulated emission of photons. Rather than amplifying light energy, the maser amplifies the lower frequency, longer wavelength microwaves and radio frequency emissions. The sun also emits microwave radiation, although most of it is blocked by Earth’s atmosphere. The Cosmic Microwave Background Radiation (CMBR), also known as relic radiation, (CMB/CBR/MBR), a thermal radiation filling the observable universe almost uniformly, in physical cosmology (a branch of astronomy that studies the largest-scale structures and dynamics of the universe and concerned with fundamental questions about its formation and evolution, is a source of microwaves that supports the science of cosmology’s Big Bang theory, a prevailing cosmological model that explains the origin of the Universe, commonly defines a the totality of everything that exists, including all mater and energy, the planets, stars, galaxies, and the contents of intergalactic space. </p><strong>About the Author:</strong><br />Johnny Diaz<br> Eagan, Minnesotta<br> <a rel="nofollow" href="http://www.newsat.com/Satellites/kaband.html">Ka Band</a><p> Article Source: <a href='http://www.articleseen.com/Article_Microwave-Sources_144802.aspx'> http://www.articleseen.com/Article_Microwave Sources_144802.aspx</a></p>

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Keywords : ka band, microwave, microwave sources, vacuum,

Category : Communications : Communications