When was the first microwave made?
Timeline of United States inventions (1890–1945)
A microwave oven cooks or heats food by dielectric heating. Cooking food with microwaves was discovered by Percy Spencer on October 8, 1945, while building magnetrons for radar sets at Raytheon. Spencer was working on an active radar set when he noticed a strange sensation, and saw that a peanut candy bar he had in his pocket started to melt. Although he was not the first to notice this phenomenon, as the holder of 120 patents, Spencer was no stranger to discovery and experiment, and realized what was happening. The radar had melted his candy bar with microwaves. The first food to be deliberately cooked with microwaves was popcorn, and the second was an egg. In 1947, Raytheon under Percy Spencer demonstrated the world's first microwave oven built at the company which was called the "Radarange".
Microwave oven
A microwave oven heats food by passing microwave radiation through it. Microwaves are a form of non-ionizing electromagnetic radiation with a frequency higher than ordinary radio waves but lower than infrared light. Microwave ovens use frequencies in one of the ISM (industrial, scientific, medical) bands, which are reserved for this use, so they do not interfere with other vital radio services. Consumer ovens usually use 2.45 gigahertz (GHz)— It is a wavelength of —while large industrial/commercial ovens often use 915 megahertz (MHz)—. Water, fat, and other substances in the food absorb energy from the microwaves in a process called dielectric heating. Many molecules (such as those of water) are electric dipoles, meaning that they have a partial positive charge at one end and a partial negative charge at the other, and therefore rotate as they try to align themselves with the alternating electric field of the microwaves. Rotating molecules hit other molecules and put them into motion, thus dispersing energy. This energy, dispersed as molecular rotations, vibrations and/or translations in solids and liquids raises the temperature of the food, in a process similar to heat transfer by contact with a hotter body It is a common misconception that microwave ovens heat food by operating at a special resonance of water molecules in the food. As noted microwave ovens can operate at many frequencies.
Microphone
Also in 1923, the ribbon microphone was introduced, another electromagnetic type, believed to have been developed by Harry F. Olson, who essentially reverse-engineered a ribbon speaker. Over the years these microphones were developed by several companies, most notably RCA that made large advancements in pattern control, to give the microphone directionality. With television and film technology booming there was demand for high fidelity microphones and greater directionality. Electro-Voice responded with their Academy Award-winning shotgun microphone in 1963.
During the second half of 20th century development advanced quickly with the Shure Brothers bringing out the SM58 and SM57. The latest research developments include the use of fibre optics, lasers and interferometers.
Amana Corporation
In 1954, it began making air conditioners. Amana was acquired in 1965 by Raytheon, which had invented the microwave oven in 1947, and introduced the commercial "Radarange" Model 1611 in 1954. In 1967, Amana introduced a consumer model of the "Radarange", the first popular microwave designed for home use.
Aaron L. Brody
Brody started his career, while in school, in food technology with the Birdseye Fisheries Lab Division of General Foods in 1951 as a team member in the development of the first frozen precooked foods including fish sticks. While a graduate student, he worked part-time for Raytheon Manufacturing Company where he was a member of a team that developed the first microwave oven, leading to microwave cooking, heating, and browning of foods. After he earned his graduate degree, Brody worked for the Whirlpool Corporation in Benton Harbor, Michigan. He led the development of modified atmosphere packaging (MAP), invented an odor control system for refrigerators, a thermoelectric refrigerator/freezer, the Total Environmental Control “Tectrol” controlled atmosphere process for food preservation, a progenitor of MAP fresh-cut vegetables, and radiation pasteurization of foods. While at Whirlpool, he invented and patented an apparatus and method of storing perishable animal and plant materials, as well as non-food materials.
Valve microphone
Vacuum tube or electronic valve amplifiers were first used to resolve microphone impedance and output problems. Bell Labs invented the condenser microphones in 1917 and this type of microphone went through many stages of improvement. Because of the invention of valve amplifiers, the production of simple moving coil mics like the Western designed 630A "8 Ball" became possible. This dynamic microphone went on to become one of the mainstays of American microphone production. In this period valves were also then incorporated internally into microphones and valve microphones were hence commercially available.
Microwave oven
Another misconception is that microwave ovens cook food "from the inside out", meaning from the center of the entire mass of food outwards. This idea arises from heating behavior seen if an absorbent layer of water lies beneath a less absorbent drier layer at the surface of a food; in this case, the deposition of heat energy inside a food can exceed that on its surface. This can also occur if the inner layer has a lower heat capacity than the outer layer causing it to reach a higher temperature, or even if the inner layer is more thermally conductive than the outer layer making it feel hotter despite having a lower temperature. In most cases, however, with uniformly structured or reasonably homogenous food item, microwaves are absorbed in the outer layers of the item at a similar level to that of the inner layers. Depending on water content, the depth of initial heat deposition may be several centimetres or more with microwave ovens, in contrast to broiling/grilling (infrared) or convection heating—methods which deposit heat thinly at the food surface. Penetration depth of microwaves is dependent on food composition and the frequency, with lower microwave frequencies (longer wavelengths) penetrating further.
W. A. S. Butement
In February 1940, Harry Boot and John Randall at Birmingham University built a high-power cavity magnetron, allowing signal-generation at microwave frequencies. In the autumn of 1940, the device was brought to America by the Tizard Mission, and development of microwave radars was started on both sides of the Atlantic. (The Tizard Mission also brought back to Great Britain the name 'radar' – adopted as a cover by the US Navy in 1940.)
Mallika-E-Kitchen
Each episode consists of a cookery competition between two women who prepare the same dish; however, one of them prepares it on the traditional gas stove and other concocts it in a microwave oven in a deadline of 20 minutes. The food concocted is first commented by a chef and then tasted by the celebrity guest, who is supposed to guess whether the dish (s)he liked was made on microwave or stove. The name of the winner is kept anonymous until the guest decides which one was the best. The winner is given the title of "LG Mallia-E-Kitchen" and an LG microwave oven from regional director(s) of LG.
Microwave enhanced electrochemistry
Microwave radiation was applied in electrochemical methods in 1998 when Frank Marken and Richard G. Compton in Oxford placed a piece of platinum wire inside a microwave cavity in small electrochemical cell.
Cosmic background radiation
1946:
The term "microwave" is first used in print in an astronomical context in an article "Microwave Radiation from the Sun and Moon" by Robert Dicke and Robert Beringer.
Electromagnetic spectrum
Microwaves are radio waves of short wavelength, from about 10 centimeters to one millimeter, in the SHF and EHF frequency bands. Microwave energy is produced with klystron and magnetron tubes, and with solid state devices such as Gunn and IMPATT diodes. Although they are emitted and absorbed by short antennas, they are also absorbed by polar molecules, coupling to vibrational and rotational modes, resulting in bulk heating. Unlike higher frequency waves such as infrared and light which are absorbed mainly at surfaces, microwaves can penetrate into materials and deposit their energy below the surface. This effect is used to heat food in microwave ovens, and for industrial heating and medical diathermy. Microwaves are the main wavelengths used in radar, and are used for satellite communication, and wireless networking technologies such as Wi-Fi, although this is at intensity levels unable to cause thermal heating. The copper cables (transmission lines) which are used to carry lower frequency radio waves to antennas have excessive power losses at microwave frequencies, and metal pipes called waveguides are used to carry them. Although at the low end of the band the atmosphere is mainly transparent, at the upper end of the band absorption of microwaves by atmospheric gasses limits practical propagation distances to a few kilometers.
Telecommunications towers in the United Kingdom
The first UK microwave relay towers were built in about 1952 for a television link between Manchester and Kirk o'Shotts near Glasgow. A chain of 14 towers, known as "backbone", running from the Chilterns to Scotland and intended primarily for national defence in the Cold War, was first mentioned publicly in the 1955 Defence White Paper. It announced "The Post Office are planning to build up a special network, both by cable and radio, designed to maintain long distance communication in the event of an attack". It wasn't actually built until the early 1960s, by which time the original Backbone concept had become absorbed into a much larger microwave network built for a mixture of civil and defence traffic including voice, telegraphy, television and radar.
Waveguide (electromagnetism)
The development of centimeter radar during World War 2 and the first high power microwave tubes, the klystron (1938) and cavity magnetron (1940), resulted in the first widespread use of waveguide. Standard waveguide "plumbing" components were manufactured, with flanges on the end which could be bolted together. After the war in the 1950s and 60s waveguides became common in commercial microwave systems, such as airport radar and microwave relay networks which were built to transmit telephone calls and television programs between cities.
Raytheon
Raytheon's research on the magnetron tube revealed the potential of microwaves to cook food. In 1945, Raytheon's Percy Spencer invented the microwave oven by discovering that the magnetron could rapidly heat food. In 1947, the company demonstrated the Radarange microwave oven for commercial use.
Thermal rocket
The microwave thermal rocket was invented by Kevin L.G. Parkin in 2002 and was the subject of his Ph.D. dissertation. Between May 2012 and March 2014, the DARPA/NASA millimeter-wave thermal launch system (MTLS) project continued this work, culminating in the first microwave thermal rocket launch in February 2014. Several launches were attempted but problems with the beam director could not be resolved before funding ran out in March 2014.
Megaphone
Although electronic public address systems have existed since vacuum tube amplifiers were developed in the early 1920s, vacuum tube versions were too heavy to be portable. Practical portable electric megaphones had to await the development of microelectronics which followed the invention of the transistor in 1947. In 1954, TOA Corporation developed the EM-202, the world's first transistorized megaphone.
Microwave oven
In 2000, some manufacturers began offering high power quartz halogen bulbs to their convection microwave models, marketing them under names such as "Speedcook", "Advantium", "Lightwave" and "Optimawave" to emphasize their ability to cook food rapidly and with good browning. The bulbs heat the food's surface with infrared (IR) radiation, browning surfaces as in a conventional oven. The food browns while also being heated by the microwave radiation and heated through conduction through contact with heated air. The IR energy which is delivered to the outer surface of food by the lamps is sufficient to initiate browning caramelization in foods primarily made up of carbohydrates and Maillard reactions in foods primarily made up of protein. These reactions in food produce a texture and taste similar to that typically expected of conventional oven cooking rather than the bland boiled and steamed taste that microwave-only cooking tends to create.
History of electronic engineering
In 1969, Ted Hoff conceived the commercial microprocessor at Intel and thus ignited the development of the personal computer. Hoff's invention was part of an order by a Japanese company for a desktop programmable electronic calculator, which Hoff wanted to build as cheaply as possible. The first realization of the microprocessor was the Intel 4004, a 4-bit processor, in 1969, but only in 1973 did the Intel 8080, an 8-bit processor, make the building of the first personal computer, the MITS Altair 8800, possible. The first PC was announced to the general public on the cover of the January 1975 issue of Popular Electronics.
Vigilant Eagle
Raytheon's experimentation with directed energy weapons began when its research labs' experiments had inadvertently produced the first microwave oven in 1958. Under William Swanson, Raytheon’s chairman and CEO, the company has become even more focused on directed energy systems. He has stated "When I look at directed energy, it's clear that if someone is gonna put us out of business, it will be us."
Act II (popcorn)
Act II is a brand of microwave popcorn in North America that is ostensibly based on the look and taste of movie theater popcorn. It is currently made and distributed by Conagra Brands. Act II was preceded in the popcorn market by Act I, an early microwave popcorn that had to be stored in the refrigerator due its real butter content. Act I was introduced in 1981. In 1984, Act II, a shelf stable microwave popcorn was released, becoming the first mass-marketed microwave popcorn.
Microphone
The condenser microphone, invented at Western Electric in 1916 by E. C. Wente, is also called a capacitor microphone or electrostatic microphone—capacitors were historically called condensers. Here, the diaphragm acts as one plate of a capacitor, and the vibrations produce changes in the distance between the plates. There are two types, depending on the method of extracting the audio signal from the transducer: DC-biased microphones, and radio frequency (RF) or high frequency (HF) condenser microphones. With a DC-biased microphone, the plates are biased with a fixed charge ("Q"). The voltage maintained across the capacitor plates changes with the vibrations in the air, according to the capacitance equation (C = ), where Q = charge in coulombs, C = capacitance in farads and V = potential difference in volts. The capacitance of the plates is inversely proportional to the distance between them for a parallel-plate capacitor. The assembly of fixed and movable plates is called an "element" or "capsule".
Oven
More recently, ovens have become slightly more high-tech in terms of cooking strategy. The microwave as a cooking tool was discovered by Percy Spencer in 1946, and with the help from engineers, the microwave oven was patented. The microwave oven uses microwave radiation to excite the molecules in food causing friction, thus producing heat.In cooking, the conventional oven is a kitchen appliance used for roasting and heating. Foods normally cooked in this manner include meat, casseroles and baked goods such as bread, cake and other desserts. In modern times, the oven is used to cook and heat food in many households across the globe.
Microwave oven
Microwave ovens are a common kitchen appliance and are popular for reheating previously cooked foods and cooking a variety of foods. They are also useful for rapid heating of otherwise slowly prepared foodstuffs, which can easily burn or turn lumpy when cooked in conventional pans, such as hot butter, fats, chocolate or porridge. Unlike conventional ovens, microwave ovens usually do not directly brown or caramelize food, since they rarely attain the necessary temperatures to produce Maillard reactions. Exceptions occur in rare cases where the oven is used to heat frying-oil and other very oily items (such as bacon), which attain far higher temperatures than that of boiling water.
Robert V. Decareau
Robert Vincent Decareau (May 26, 1926 – January 18, 2009) was an American food scientist who was involved in the development of microwave applications in food technology, specifically technology that would lead to the development of the microwave oven. He also served in the United States Navy during World War II and in the United States Army during the Korean War. Decareau also was charter member of Phi Tau Sigma while pursuing his Ph.D. at the University of Massachusetts Amherst.
Electromagnetic spectrum
Maxwell's predicted waves included waves at very low frequencies compared to infrared, which in theory might be created by oscillating charges in an ordinary electrical circuit of a certain type. Attempting to prove Maxwell's equations and detect such low frequency electromagnetic radiation, in 1886 the physicist Heinrich Hertz built an apparatus to generate and detect what are now called radio waves. Hertz found the waves and was able to infer (by measuring their wavelength and multiplying it by their frequency) that they traveled at the speed of light. Hertz also demonstrated that the new radiation could be both reflected and refracted by various dielectric media, in the same manner as light. For example, Hertz was able to focus the waves using a lens made of tree resin. In a later experiment, Hertz similarly produced and measured the properties of microwaves. These new types of waves paved the way for inventions such as the wireless telegraph and the radio.
Neff GmbH
In 1957, it introduced the first microwave oven. In 1957, it introduced the first induction cooker (hob) in Europe, marketing it under the revolutionary slogan of "Kochen auf der kalten Platte" (cook on a cold surface). In 1961 it introduced the first integrated cooker units in Europe, built into other kitchen units - the built-in oven. Also in the same year they began selling larger microwave cookers for commercial (catering) uses. By 1970 it was branching out into providing for the full range of units to make up a fitted kitchen. By the early 1970s the cookers were among the first to be controlled with a digital clock.
History of watches
The watch is based on a chip developed by the breakthrough Chip Scale Atomic Clock (CSAC) program of the US Defense Advanced Research Projects Agency (DARPA) which was initiated in 2001, and produced the first prototype atomic clock chip in 2005. Symmetricom began manufacturing the chips in 2011. Like other cesium clocks the watch keeps time with an ultraprecise 9.192631770 GHz microwave signal produced by electron transitions between two hyperfine energy levels in atoms of cesium, which is divided down by digital counters to give a 1 Hz clock signal to drive the hands. On the chip, liquid metal cesium in a tiny capsule is heated to vaporize the cesium. A laser shines a beam of infrared light modulated by a microwave oscillator through the capsule onto a photodetector. When the oscillator is at the precise frequency of the transition, the cesium atoms absorb the light, reducing the output of the photodetector. The output of the photodetector is used as feedback in a phase locked loop circuit to keep the oscillator at the correct frequency. The breakthrough that allowed a rack-sized cesium clock to be shrunk small enough to fit on a chip was a technique called coherent population trapping, which eliminated the need for a bulky microwave cavity.
The Terry and Gaby Show
One of the most memorable moments of the show's short history came when Baker placed a piece of soap in a microwave oven. Although an oven glove had been provided for protection, Baker failed to use it, resulting in him burning his hand when he took the plate out of the microwave to the great amusement of the audience, before removing the glass plate from the microwave which promptly shattered on the floor. The clip is a well-known out-take.
Microwave
In 1931 an Anglo-French consortium demonstrated the first experimental microwave relay link, across the English Channel between Dover, UK and Calais, France. The system transmitted telephony, telegraph and facsimile data over bidirectional 1.7 GHz beams with a power of one-half watt, produced by miniature Barkhausen-Kurz tubes at the focus of metal dishes.
Microwave burn
The first microwave oven injury was reported in 1973. Two women operated a microwave oven in a department store snack bar. After several years, the oven showed a malfunction manifesting by burning the food. The first woman noticed burning sensations in her fingers and very little pain or tenderness when nearby to the operating oven. A small lesion appeared on her left index finger, near the base of the fingernail. In the next four weeks, three fingers of her right hand became affected as well. Transverse ridging and deformations close to the nail base appeared on her fingernails. After five months since the initial symptoms, she visited a doctor; the examination found no abnormalities other than the nails. Topical steroid cream used over six weeks led to gradual improvement. The second woman experienced nail deformation at the same time as the first one, with the same clinical findings. The oven was returned to the manufacturer before the involvement of the doctor, and the amount of leakage could not be assessed.
Baked Alaska
In 1969, the recently invented microwave oven enabled Hungarian gastrophysicist Nicholas Kurti to produce a reverse baked Alaska (also called a "Frozen Florida")—a frozen shell of meringue filled with hot liquor.
1970s in science and technology
During the 1970s, microwave ovens experienced a surge in popularity as price and size decreased rapidly towards the end of the decade. Cassette tapes continued to surge in popularity after their introduction in the 1960s. JVC's VHS and Sony's Betamax waged a videotape format war as the primary recording and video devices beginning in 1976, but by the end of the decade VHS had become the dominant format. Also introduced to the home market was the Laserdisc, the first optical disc format used primarily for high quality video.
WSAZ-TV
In 1950, WSAZ-TV received Federal Communications Commission (FCC) permission to build a private microwave link to Cincinnati allowing viewers to get NBC programming live. As the nation's first privately owned microwave system, it was a remarkable feat for one of the smallest cities in the country at the time to have a television station. The first live broadcast was scheduled for a Labor Day baseball game, but the system broke down for four hours and forced WSAZ to broadcast a fire at a nearby hotel. The Cincinnati link was replaced in favor of one from Columbus, Ohio in 1952.
Kinjiro Okabe
Okabe first published his findings in a Japanese journal, and followed with a foundational paper in the prestigious "Proceedings of the IRE". While Hull had published on the HF magnetron years earlier, it was only after Okabe’s detailed paper on generation at 17 cm that this device gained world interest. Although this was the first microwave magnetron, it was not immediately applied in communications because it was not frequency stable.
Xinu
The first successful port of embedded Xinu was in 1994, when it was implemented in a Kenmore model 728858 microwave oven produced in the year 1990.
Microwave oven
The invention of the cavity magnetron made possible the production of electromagnetic waves of a small enough wavelength (microwaves). The magnetron was originally a crucial component in the development of short wavelength radar during World War II. In 1937–1940, a multi-cavity magnetron was built by the British physicist Sir John Turton Randall, FRSE, together with a team of British coworkers, for the British and American military radar installations in World War II. A more high-powered microwave generator that worked at shorter wavelengths was needed, and in 1940, at the University of Birmingham in England, Randall and Harry Boot produced a working prototype. They invented a valve that could spit out pulses of microwave radio energy on a wavelength of 10 cm, an unprecedented discovery.
Microwave chemistry
Microwave chemistry is the science of applying microwave radiation to chemical reactions. Microwaves act as high frequency electric fields and will generally heat any material containing mobile electric charges, such as polar molecules in a solvent or conducting ions in a solid. Polar solvents are heated as their component molecules are forced to rotate with the field and lose energy in collisions. Semiconducting and conducting samples heat when ions or electrons within them form an electric current and energy is lost due to the electrical resistance of the material. Microwave heating in the laboratory began to gain wide acceptance following papers in 1986, although the use of microwave heating in chemical modification can be traced back to the 1950s. Although occasionally known by such acronyms as "MAOS" (Microwave-Assisted Organic Synthesis), "MEC" (Microwave-Enhanced Chemistry) or "MORE synthesis" (Microwave-organic Reaction Enhancement), these acronyms have had little acceptance outside a small number of groups.
Sutton tube
The usable soft Sutton tube arrived in March 1941, and was put into production as the CV43. It was first used as part of the AI Mk. VII radar, the first production microwave radar for aircraft. The system was widely used from then on, appearing in almost all airborne microwave radars, including the H2S radar.
MCI Communications
In 1968, William G. McGowan, an investor from New York with experience in raising venture capital, met with the board of Microwave Communications to discuss financing plans for the business. As a result of meetings in June and July, Microwave Communications of America, Inc (MICOM) was incorporated on August 8, 1968 as an umbrella corporation to help build a nationwide microwave relay system. McGowan also made an investment into the new corporation large enough to pay all outstanding debts of the combined businesses and create a cash reserve. The investment also provided McGowan a stake in the company and a seat on the board.
Microphone
German inventor Johann Philipp Reis designed an early sound transmitter that used a metallic strip attached to a vibrating membrane that would produce intermittent current. Better results were achieved with the "liquid transmitter" design in Scottish-American Alexander Graham Bell's telephone of 1876 – the diaphragm was attached to a conductive rod in an acid solution. These systems, however, gave a very poor sound quality.
The first microphone that enabled proper voice telephony was the (loose-contact) carbon microphone. This was independently developed by David Edward Hughes in England and Emile Berliner and Thomas Edison in the US. Although Edison was awarded the first patent (after a long legal dispute) in mid-1877, Hughes had demonstrated his working device in front of many witnesses some years earlier, and most historians credit him with its invention. The carbon microphone is the direct prototype of today's microphones and was critical in the development of telephony, broadcasting and the recording industries. Thomas Edison refined the carbon microphone into his carbon-button transmitter of 1886. This microphone was employed at the first ever radio broadcast, a performance at the New York Metropolitan Opera House in 1910.
In 1916, E.C. Wente of Western Electric developed the next breakthrough with the first condenser microphone. In 1923, the first practical moving coil microphone was built. The Marconi-Sykes magnetophone, developed by Captain H. J. Round, became the standard for BBC studios in London. This was improved in 1930 by Alan Blumlein and Herbert Holman who released the HB1A and was the best standard of the day.
Charles H. Townes
During 1953, Townes, James P. Gordon, and H. J. Zeiger built the first ammonia maser at Columbia University. This device used stimulated emission in a stream of energized ammonia molecules to produce amplification of microwaves at a frequency of about 24.0 gigahertz.
Microwave
In 1894, Oliver Lodge and Augusto Righi generated 1.5 and 12 GHz microwaves respectively with small metal ball spark resonators. The same year Indian physicist Jagadish Chandra Bose was the first person to produce millimeter waves, generating 60 GHz (5 millimeter) microwaves using a 3 mm metal ball spark oscillator. Bose also invented waveguide and horn antennas for use in his experiments. Russian physicist Pyotr Lebedev in 1895 generated 50 GHz millimeter waves. In 1897 Lord Rayleigh solved the mathematical boundary-value problem of electromagnetic waves propagating through conducting tubes and dielectric rods of arbitrary shape. which gave the modes and cutoff frequency of microwaves propagating through a waveguide.
Dielectric heating
Microwave frequencies penetrate conductive materials, including semi-solid substances like meat and living tissue, to a distance defined by the skin effect. The penetration essentially stops where all the penetrating microwave energy has been converted to heat in the tissue. Microwave ovens used to heat food are not set to the frequency for optimal absorption by water. If that were so, then the piece of food or liquid in question would absorb all microwave radiation in its outer layer, leading to a cool, unheated centre and a superheated surface. Instead, the frequency selected allows energy to penetrate deeper into the heated food. The frequency of a household microwave oven is 2.45 GHz, while the frequency for optimal absorbency by water is around 10 GHz.
Pulsed electron paramagnetic resonance
R. J. Blume reported the first electron spin echo in 1958, which came from a solution of sodium in ammonia at its boiling point, -33.8˚C. A magnetic field of 0.62 mT was used requiring a frequency of 17.4 MHz. The first microwave electron spin echoes were reported in the same year by Gordon and Bowers using 23 GHz excitation of dopants in silicon.
Waltham, Massachusetts
Another first in Waltham industrial history involves the method to mass-produce the magnetron tube, invented by Percy Spencer at Raytheon. During World War II, the magnetron tube technology was applied to radar. Later, magnetron tubes were used as components in microwave ovens.
Weber Research Institute
The Microwave Research Institute (MRI) was founded in 1945 by Ernst Weber at the Polytechnic Institute of Brooklyn (which later became the Polytechnic Institute of New York University). Research conducted at the institute included work in the areas of "electromagnetic theory, antennas and radiation, network theory and microwave networks, microwave components and devices." MRI was internationally regarded as one of the foremost centers of research on microwave field theory in the world. In 1985 it was renamed the Weber Research Institute in honor of its founder.Among its most prominent members were Nathan Marcuvitz, Leo B. Felsen, Dante C. Youla and Arthur A. Oliner, all fellows of IEEE and members of the National Academy of Engineering. The institute has attracted researchers from all over the world, including Alexander Graham Bell Medal winner Tsuneo Nakahara, who in 1961 was a visiting research associate of the institute, and who went on to be vice chairman of the Sumitomo Electric Company, and Dr. Oguchi, who became chief engineer of Nippon Telegraph and Telephone. Another faculty member closely associated with MRI was KunMo Chung, Director of the Plasma Physics Laboratory from 1967 to 1975, who served as Minister of Science and Technology of South Korea two times and who was associated with numerous international science and technology agencies.
Ideal Home Show
The first microwave oven was launched at the show in 1947. In 1957 the British housewife still spent an average of 70 hours a week on housework
TrueCookPlus
In 2008, the first TrueCookPlus licensed microwave ovens were launched in a limited national test market beginning at Best Buy in August, then Sears in September. During this test market phase, Consumer Reports selected the TrueCookPlus equipped Kenmore model #6633 as its #1 Top Rated mid-sized countertop microwave oven.
Airborne Interception radar
In February 1940, John Randall and Harry Boot at Birmingham University successfully ran the first cavity magnetron, eventually generating 1 kW at 9.8 cm (3,060 MHz). Supported by GEC, the device quickly developed into a practical 10 kW system, and several test units were available by May 1940. Microwave wavelengths are so much shorter than the Mk. IV's 1.5 m, fifteen times, that the dipole antennas required for reasonable gain were only a few inches long. This dramatically reduced the size of the system, allowing it to fit entirely in the nose of the aircraft.
Microwave
During World War II, it was observed that individuals in the radiation path of radar installations experienced clicks and buzzing sounds in response to microwave radiation. This microwave auditory effect was thought to be caused by the microwaves inducing an electric current in the hearing centers of the brain. Research by NASA in the 1970s has shown this to be caused by thermal expansion in parts of the inner ear. In 1955 Dr. James Lovelock was able to reanimate rats chilled to 0-1°C using microwave diathermy.
Magic Chef
Quick Meal manufactured the stoves, with Ringen Stove handling sales and distribution of the entire output of Quick Meal's production. The phenomenal growth of these two companies during the 1880s and 1890s led to the merger of eight other stove companies in St. Louis, Chicago and Cleveland in 1901 to form the American Stove Company. American Stove introduced the first oven temperature control device in 1914.
Miniature snap-action switch
The first micro switch was invented by Phillip Kenneth McGall in 1932 in Freeport, Illinois, patent 1,960,020. McGall was an employee of the Burgess Battery Company at the time. In 1937 W.B. Schulte, McGall's employer, started the company MICRO SWITCH. The company and the "Micro Switch" trademark has been owned by Honeywell Sensing and Control since 1950. The name has become a generic trademark for any snap-action switch. Companies other than Honeywell now manufacture miniature snap-action switches.
Raytheon
In 1965, it acquired Amana Refrigeration, Inc., a manufacturer of refrigerators and air conditioners. Using the Amana brand name and its distribution channels, Raytheon began selling the first countertop household microwave oven in 1967 and became a dominant manufacturer in the microwave oven business.
Valve microphone
Microphones have been in use since the early telephone technology of the mid 1800s but achieved higher sound quality in the 1920s with the first double-button carbon mics made by Western Electric. The 387 model, with its 0.0017 inch thick gold-sputtered diaphragm, was the best of these early designs. It was followed by the improved model 600 in the early 1930s, and the double-button became recognised worldwide as a standard in broadcasting.
Microwave oven
Any object containing pointed metal can create an electric arc (sparks) when microwaved. This includes cutlery, crumpled aluminium foil (though some foil used in microwaves are safe, see below), twist-ties containing metal wire, the metal wire carry-handles in paper Chinese take-out food containers, or almost any metal formed into a poorly conductive foil or thin wire; or into a pointed shape. Forks are a good example: the tines of the fork respond to the electric field by producing high concentrations of electric charge at the tips. This has the effect of exceeding the dielectric breakdown of air, about 3 megavolts per meter (3×10 V/m). The air forms a conductive plasma, which is visible as a spark. The plasma and the tines may then form a conductive loop, which may be a more effective antenna, resulting in a longer lived spark. When dielectric breakdown occurs in air, some ozone and nitrogen oxides are formed, both of which are unhealthy in large quantities.
Bill Daniels
Daniels took a chance on this long-distance television market by setting up a microwave feed that delivered Denver programming to Casper, Wyoming in 1952. It was the first broadcast signal sent by microwave feed. His television feed had only one channel and polled his viewers every 90 days on what they preferred to watch.
Micrometer
The first ever micrometric screw was invented by William Gascoigne in the 17th century, as an enhancement of the vernier; it was used in a telescope to measure angular distances between stars and the relative sizes of celestial objects.
Microwave
Microwaves were first generated in the 1880s and 1890s in some of the earliest radio experiments by physicists who thought of them as a form of "invisible light". James Clerk Maxwell in his 1873 theory of electromagnetism, now called Maxwell's equations, had predicted the existence of electromagnetic waves and proposed that light was composed of these waves. In 1888, German physicist Heinrich Hertz was the first to demonstrate the existence of radio waves using a primitive spark gap radio transmitter. Hertz and the other early radio researchers were interested in exploring the similarities between radio waves and light waves, to test Maxwell's theory. They concentrated on producing short wavelength radio waves in the UHF and microwave ranges, with which they could duplicate classic optics experiments, using quasioptical components such as prisms and lenses made of paraffin, sulfur and pitch and wire diffraction gratings, to refract and diffract radio waves like light rays. Hertz produced waves up to 450 MHz; his directional 450 MHz transmitter consisted of a 26 cm brass rod dipole antenna with a spark gap between the ends suspended at the focal line of a parabolic antenna made of a curved zinc sheet, powered by high voltage pulses from an induction coil. His historic experiments demonstrated that radio waves like light exhibited refraction, diffraction, polarization, interference and standing waves, proving that radio waves and light waves were both forms of Maxwell's electromagnetic waves.
Waveguide (electromagnetism)
During the 1920s the first continuous sources of high frequency radio waves were developed: the Barkhausen-Kurz tube, the first oscillator which could produce power at UHF frequencies; and the split-anode magnetron which by the 1930s had generated radio waves at up to 10 GHz. These made possible the first systematic research on microwaves in the 1930s. It was discovered that transmission lines used to carry lower frequency radio waves, parallel line and coaxial cable, had excessive power losses at microwave frequencies, creating a need for a new transmission method.
Electromagnetic shielding
The door of a microwave oven has a screen built into the window. From the perspective of microwaves (with wavelengths of 12 cm) this screen finishes a Faraday cage formed by the oven's metal housing. Visible light, with wavelengths ranging between 400 nm and 700 nm, passes easily through the screen holes.
Microwave auditory effect
Allan H. Frey was the first American to publish on the microwave auditory effect (MAE). Frey's "Human auditory system response to modulated electromagnetic energy" appeared in the Journal of Applied Physiology in 1961. In his experiments, the subjects were discovered to be able to hear appropriately pulsed microwave radiation, from a distance of a few inches to hundreds of feet from the transmitter. In Frey's tests, a repetition rate of 50 Hz was used, with pulse width between 10–70 microseconds. The perceived loudness was found to be linked to the peak power density, instead of average power density. At 1.245 GHz, the peak power density for perception was below 80 mW/cm. According to Frey, the induced sounds were described as "a buzz, clicking, hiss, or knocking, depending on several transmitter parameters, i.e., pulse width and pulse-repetition rate". By changing transmitter parameters, Frey was able to induce the "perception of severe buffeting of the head, without such apparent vestibular symptoms as dizziness or nausea". Other transmitter parameters induced a pins and needles sensation. Frey experimented with nerve-deaf subjects, and speculated that the human detecting mechanism was in the cochlea, but at the time of the experiment the results were inconclusive due to factors such as tinnitus.
Thelma Pressman
Pressman studied microwave technology at California Community Colleges in 1967. In 1969 she founded the first microwave cooking school in the United States in Encino, California. The Microwave Cooking Center became an industry test kitchen in which products were evaluated and cookware and recipes were developed for the nascent microwave industry.
Food processor
One of the first electric food processors was the Starmix, introduced by German company Electrostar in 1946. Although the basic unit resembled a simple blender, numerous accessories were available, including attachments for slicing bread, milk centrifuges and ice cream bowls. In a time when electric motors were expensive, they also developed the piccolo, where the food processor's base unit could drive a vacuum cleaner. In the 1960s, Albrecht von Goertz designed the Starmix MX3 food processor. Although the entire company was rebranded as Starmix in 1968 following the success of the processors, they later focused on vacuum cleaners and electric hand-dryers and the last mixer was produced around the year 2000. 
In France, the concept of a machine to process food began when a catering company salesman, Pierre Verdun, observed the large amount of time his clients spent in the kitchen chopping, shredding and mixing. He produced a simple but effective solution, a bowl with a revolving blade in the base. In 1960, this evolved into Robot-Coupe, a company established to manufacture commercial "food processors" for the catering industry. In the late 1960s, a commercial food processor driven by a powerful commercial induction motor was produced. Robot-Coupe's Magimix food processor arrived from France in the UK in 1974, beginning with the Model 1800. Then, a UK company Kenwood Limited started their own first Kenwood Food Processor, 'processor de- luxe,' in 1979.
Microwave
A microwave oven passes microwave radiation at a frequency near  through food, causing dielectric heating primarily by absorption of the energy in water. Microwave ovens became common kitchen appliances in Western countries in the late 1970s, following the development of less expensive cavity magnetrons. Water in the liquid state possesses many molecular interactions that broaden the absorption peak. In the vapor phase, isolated water molecules absorb at around 22 GHz, almost ten times the frequency of the microwave oven.
Science and invention in Birmingham
At some time around the late 18th or early 19th century a stand-alone cooking range or stove is invented by John Heard (joiner), capable of roasting, boiling, baking and of course heating a room. The products of combustion are carried off by means of a flue leading to the chimney, the inventor mentions it is particularly suitable for use on board ships. This is possibly the first of its kind, as earlier stoves such as the Franklin stove do not appear to have flues attached and require a hearth and chimney to function, also it is not until the turn of the 19th century that other stoves begin appearing for cooking as well as heating a room.
Cosmic background radiation
1931:
The term "microwave" first appears in print: "When trials with wavelengths as low as 18 cm were made known, there was undisguised surprise that the problem of the micro-wave had been solved so soon." "Telegraph & Telephone Journal" XVII. 179/1"
Microwave
Prior to the 1970s microwave devices and circuits were bulky and expensive, so microwave frequencies were generally limited to the output stage of transmitters and the RF front end of receivers, and signals were heterodyned to a lower intermediate frequency for processing. The period from the 1970s to the present has seen the development of tiny inexpensive active solid state microwave components which can be mounted on circuit boards, allowing circuits to perform significant signal processing at microwave frequencies. This has made possible satellite television, cable television, GPS devices, and modern wireless devices, such as smartphones, Wi-Fi, and Bluetooth which connect to networks using microwaves.
Microwave radiometer
First developments of microwave radiometer were dedicated to the measurement of radiation of extraterrestrial origin in the 1930s and 1940s. The most common form of microwave radiometer was introduced by Robert Dicke in 1946 in the Radiation Laboratory of Massachusetts Institute of Technology to better determine the temperature of the microwave background radiation. This first radiometer worked at a wavelength 1.25 cm and was operated at the Massachusetts Institute of Technology. Dicke also first discovered weak atmospheric absorption in the MW using three different radiometers (at wavelengths of 1.0, 1.25 and 1.5 cm).
Maser
Independently, Charles Hard Townes, James P. Gordon, and H. J. Zeiger built the first ammonia maser at Columbia University in 1953. This device used stimulated emission in a stream of energized ammonia molecules to produce amplification of microwaves at a frequency of about 24.0 gigahertz. Townes later worked with Arthur L. Schawlow to describe the principle of the "optical maser", or "laser", of which Theodore H. Maiman created the first working model in 1960.
Augusto Righi
Righi was the first person to generate microwaves, and opened a whole new area of the electromagnetic spectrum to research and subsequent applications. His work "L'ottica delle oscillazioni elettriche" (1897), which summarised his results, is considered a classic of experimental electromagnetism. By 1900 he had begun to work on X-rays and the Zeeman Effect. In 1903 he wrote the first paper on wireless telegraphy. He also studied gas under various conditions of pressure and ionization, and worked on improvements to the Michelson–Morley experiment from 1918.
History of the hamburger
The first automobile production line was created by Karl Benz in Germany in 1888. The widespread appearance of telephones occurred at the beginning of the 20th century, along with other modern means of communication, including radio. For the average American who had not eaten in a restaurant in his or her entire life, the fast food chains that appeared in the cities offered an alternative form of restaurant in which eating was very much a public activity. The concept of a "greasy spoon" was thus born with these restaurants, in which hygiene suffered in exchange for more inexpensive food. On the other hand, there was a growing interconnected world in which trips by car, bus, and rail became increasingly available. All these means of transport were improving at the time, and soon it was necessary to feed a growing population that was "in permanent transit", frequently moving through different cities on business. George Pullman invented the sleeping car and the dining car in response to the needs of these people in the 1870s. Similarly, the English immigrant Frederick Henry Harvey was the first to use "dynamic mass movement" in restoring the Fred Harvey Company, which catered to the patrons of a chain of hotels located near railway stations, as well as offering catering, services, and high quality products on the trains themselves.
Microwave oven
The development of the cavity magnetron in the UK made possible the production of electromagnetic waves of a small enough wavelength (microwaves). American engineer Percy Spencer is generally credited with inventing the modern microwave oven after World War II from radar technology developed during the war. Named the "Radarange", it was first sold in 1946. Raytheon later licensed its patents for a home-use microwave oven that was first introduced by Tappan in 1955, but these units were still too large and expensive for general home use. Sharp Corporation introduced the first microwave oven with a turntable between 1964 and 1966. The countertop microwave oven was first introduced in 1967 by the Amana Corporation. After Sharp introduced low-cost microwave ovens affordable for residential use in the late 1970s, their use spread into commercial and residential kitchens around the world. In addition to their use in cooking food, types of microwave ovens are used for heating in many industrial processes.
Kitchen stove
Microwave ovens were developed in the 1940s, and use microwave radiation to directly heat the water held inside food.
Hot Pockets
Hot Pockets were developed by Paul Merage and his brother David, through their company Chef America Inc. Chef America invented a packaging sleeve and dough formula to keep its calzone-like sandwiches crispy when cooked in a microwave. In 1980, Chef America introduced its first stuffed sandwich, the Tastywich, the predecessor of the Hot Pocket. Hot Pockets supplanted Tastywiches in 1983, first sold to restaurants because they were easier to break into than retail stores. On May 22, 2002, Chef America was sold to Nestlé. Hot Pocket products were "a $2 billion category of frozen sandwiches and snacks". Breakfast style Hot Pockets were introduced in 2001.
MCI Communications
Following the FCC approval for MCI to begin building microwave relay stations between Chicago and St. Louis, Microwave Communications of America began to form subsidiary corporations and file applications with the FCC to create microwave relays between other city pairs. Between September 1969 and February 1971, fifteen new regional carriers were created, allowing for interconnection between a number of major cities in the United States. In July 1969, MICOM also purchased an equity position in Interdata, an independent regional carrier that was applying to build a microwave relay chain between New York City and Washington, D.C.
MCI began selling data transmission services to paying customers on January 1, 1972.
History of electrical engineering
The invention of the transistor in 1947 by William B. Shockley, John Bardeen and Walter Brattain opened the door for more compact devices and led to the development of the integrated circuit in 1958 by Jack Kilby and independently in 1959 by Robert Noyce. In the mid to late 1950s, the term radio engineering gradually gave way to the name electronics engineering, which then became a stand-alone university degree subject, usually taught alongside electrical engineering with which it had become associated due to some similarities. In 1968 Marcian Hoff invented the first microprocessor at Intel and thus ignited the development of the personal computer. The first realization of the microprocessor was the Intel 4004, a 4-bit processor developed in 1971, but only in 1973 did the Intel 8080, an 8-bit processor, make the building of the first personal computer, the Altair 8800, possible.
Henry Evelyn Derek Scovil
Scovil received his D. Phil. in 1951 from University of Oxford for his thesis "Investigation of Paramagnetic Substances at Centimetre Wave-Lengths", studied paramagnetic resonance at Clarendon Laboratory, then moved to Bell Labs where he, George Feher, and H. Seidel built the first tunable, solid state maser. In the late 1950s he and colleagues constructed ruby travelling wave masers, cooled to 4.2K by liquid helium, which were then the world's lowest-noise microwave amplifiers. They were used by Arno Penzias and Robert Woodrow Wilson in their investigations of the cosmic microwave background.
Carbon microphone
The first microphone that enabled proper voice telephony was the (loose-contact) carbon microphone (then called transmitter). This was independently developed around 1878 by David Edward Hughes in England and Emile Berliner and Thomas Edison in the US. Although Edison was awarded the first patent in mid-1877, Hughes had demonstrated his working device in front of many witnesses some years earlier, and most historians credit him with its invention.
Parametric oscillator
The varactor diode invented in 1956 had a nonlinear capacitance that was usable into microwave frequencies. The varactor parametric amplifier was developed by Marion Hines in 1956 at Western Electric. At the time it was invented microwaves were just being exploited, and the varactor amplifier was the first semiconductor amplifier at microwave frequencies. It was applied to low noise radio receivers in many areas, and has been widely used in radio telescopes, satellite ground stations, and long range radar. It is the main type of parametric amplifier used today. Since that time parametric amplifiers have been built with other nonlinear active devices such as Josephson junctions. The technique has been extended to optical frequencies in optical parametric oscillators and amplifiers which use nonlinear crystals as the active element.
Amana Colonies
In 1947, the company produced the first commercial upright freezer. Two years later, the Amana Society sold off the Electrical Department to an investment group organized by Foerstner. Renamed Amana Refrigeration, Inc., the company grew to manufacture refrigerators and air conditioners. The Raytheon Corporation purchased Amana Refrigeration on January 1, 1965, although the Amana division was mostly autonomous. Amana produced the first practical commercial microwave oven in 1967. The division was sold to Goodman Global in 1997 and then sold to Maytag in 2001. It became part of the Whirlpool Corporation when it purchased Maytag in 2006.
Microwave transmission
The history of radio relay communication began in 1898 from the publication by Johann Mattausch in Austrian journal, Zeitschrift für Electrotechnik. But his proposal was primitive and not suitable for practical use. The first experiments with radio repeater stations to relay radio signals were done in 1899 by Emile Guarini-Foresio. However the low frequency and medium frequency radio waves used during the first 40 years of radio proved to be able to travel long distances by ground wave and skywave propagation. The need for radio relay did not really begin until the 1940s exploitation of microwaves, which traveled by line of sight and so were limited to a propagation distance of about by the visual horizon. 
In 1931 an Anglo-French consortium headed by Andre C. Clavier demonstrated an experimental microwave relay link across the English Channel using dishes. Telephony, telegraph, and facsimile data was transmitted over the bidirectional 1.7 GHz beams between Dover, UK, and Calais, France. The radiated power, produced by a miniature Barkhausen-Kurz tube located at the dish's focus, was one-half watt. A 1933 military microwave link between airports at St. Inglevert, France, and Lympne, UK, a distance of , was followed in 1935 by a 300 MHz telecommunication link, the first commercial microwave relay system.
Yoji Ito
In parallel with the VHF work, Yoji Ito also returned to the magnetron applications, resulting in Japan’s first pulse-modulated microwave RRF set. It operated at 10 cm (3 GHz) and produced a peak-power of 2.0 kW. A prototype was tested in October 1941, and several versions for surface ships and submarines were soon put into production. Naval officials favored the microwave sets because with very narrow beams they were less vulnerable to interception.
Mite
Mites were first observed under the microscope by the English polymath Robert Hooke. In his 1665 book "Micrographia", he stated that far from being spontaneously generated from dirt, they were "very prettily shap'd Insects". The world's first science documentary featured cheese mites, seen under the microscope; the short film was shown in London's Alhambra music hall in 1903, causing a boom in the sales of simple microscopes. A few years later, Arthur Conan Doyle wrote a satirical poem, "Parable", with the conceit of some cheese mites disputing the origin of the round Cheddar cheese in which they all lived.
Microwave
The ability of short waves to quickly heat materials and cook food had been investigated in the 1930s by I. F. Mouromtseff at Westinghouse, and at the 1933 Chicago World's Fair demonstrated cooking meals with a 60 MHz radio transmitter. In 1945 Percy Spencer, an engineer working on radar at Raytheon, noticed that microwave radiation from a magnetron oscillator melted a candy bar in his pocket. He investigated cooking with microwaves and invented the microwave oven, consisting of a magnetron feeding microwaves into a closed metal cavity containing food, which was patented by Raytheon on 8 October 1945. Due to their expense microwave ovens were initially used in institutional kitchens, but by 1986 roughly 25% of households in the U.S. owned one. Microwave heating became widely used as an industrial process in industries such as plastics fabrication, and as a medical therapy to kill cancer cells in microwave hyperthermy.
Walter E. Hussman Sr.
Hussman extended Palmer's technological achievements. In 1963, he launched the first terrestrial microwave high-speed, high-definition facsimile network ito connect a group of newspapers. This allowed the company to purchase expensive cold type composition equipment, to handle all advertising production in one city and sharing those ads with the entire group of newspapers. Typesetting of news copy also was available from this shared facility. Hussman got the idea of microwave from having visited newspaper operations in Japan.
Microwave oven
The lower temperature of cooking (the boiling point of water) is a significant safety benefit compared to baking in the oven or frying, because it eliminates the formation of tars and char, which are carcinogenic. Microwave radiation also penetrates deeper than direct heat, so that the food is heated by its own internal water content. In contrast, direct heat can burn the surface while the inside is still cold. Pre-heating the food in a microwave oven before putting it into the grill or pan reduces the time needed to heat up the food and reduces the formation of carcinogenic char. Unlike frying and baking, microwaving does not produce acrylamide in potatoes, however unlike deep-frying, it is of only limited effectiveness in reducing glycoalkaloid (i.e., solanine) levels. Acrylamide has been found in other microwaved products like popcorn.
Microwave radiometer
Soon after satellites were first used for observing the atmosphere, MW radiometers became part of their instrumentation. In 1962 the Mariner-2 mission was launched by NASA in order to investigate the surface of Venus including a radiometer for water vapor and temperature observations. In following years a wide variety of microwave radiometers were tested on satellites. The launch of the Scanning Multichannel Microwave Radiometer in 1978 became an important milestone in the history of radiometry. It was the first time a conically scanning radiometer was used in space; it was launched into space on board the NASA Nimbus satellite. The launch of this mission gave the opportunity to image the Earth at a constant angle of incidence that is important as surface emissivity is angular dependent. In the beginning of 1980, new multi-frequency, dual-polarization radiometric instruments were developed. Two spacecraft were launched which carried instruments of this type: Nimbus-7 and Seasat. The Nimbus-7 mission results allowed to globally monitor the state of ocean surface as well as surface covered by snow and glaciers. Today, microwave instruments like the Advanced Microwave Sounding Unit (AMSU) and the Special Sensor Microwave Imager / Sounder (SSMIS) are widely used on different satellites.
Microphone
Early microphones did not produce intelligible speech, until Alexander Graham Bell made improvements including a variable-resistance microphone/transmitter. Bell's liquid transmitter consisted of a metal cup filled with water with a small amount of sulfuric acid added. A sound wave caused the diaphragm to move, forcing a needle to move up and down in the water. The electrical resistance between the wire and the cup was then inversely proportional to the size of the water meniscus around the submerged needle. Elisha Gray filed a caveat for a version using a brass rod instead of the needle. Other minor variations and improvements were made to the liquid microphone by Majoranna, Chambers, Vanni, Sykes, and Elisha Gray, and one version was patented by Reginald Fessenden in 1903. These were the first working microphones, but they were not practical for commercial application. The famous first phone conversation between Bell and Watson took place using a liquid microphone.
Microwave
The traveling wave tube (TWT) developed in 1943 by Rudolph Kompfner and John Pierce provided a high-power tunable source of microwaves up to 50 GHz, and became the most widely used microwave tube (besides the ubiquitous magnetron used in microwave ovens). The gyrotron tube family developed in Russia could produce megawatts of power up into millimeter wave frequencies, and is used in industrial heating and plasma research, and to power particle accelerators and nuclear fusion reactors.
Robert V. Decareau
After earning his Ph.D in 1955, Decareau worked for Raytheon in Allston on microwave technology that would lead to the development of the microwave oven. Decareau's wife, Rosa, commented that a lot of work on the microwave oven was done at their home. Then at Lipton, he was involved in freeze drying. In the 1960s, Decareau moved to Palo Alto, California to work with Litton Industries. While at Litton, he developed microwave ovens that would be the foundation of commercial versions. Decareau moved back to Natick, Massachusetts later in his career to work in research and development at the United States Army Soldier Systems Center to develop food processing techniques for military and space exploration applications. His work would earn him Fellowship of the Institute of Food Technologists in 1994. During his career, Decareau was one of the first people to refer to himself as a food scientist.
History of radar
During 1933, Kühnhold first attempted to test this concept with a transmitting and receiving set that operated in the microwave region at 13.5 cm (2.22 GHz). The transmitter used a Barkhausen-Kurz tube (the first microwave generator) that produced only 0.1 watt. Unsuccessful with this, he asked for assistance from Paul-Günther Erbslöh and Hans-Karl Freiherr von Willisen, amateur radio operators who were developing a VHF system for communications. They enthusiastically agreed, and in January 1934, formed a company, "Gesellschaft für Elektroakustische und Mechanische Apparate" (GEMA), for the effort. From the start, the firm was always called simply GEMA.
Radar in World War II
In the spring of 1943, German submarines started operating just outside the Saint Lawrence Seaway – the primary ship route from Canada to Great Britain. To counter this, the Royal Canadian Air Force (RCAF) asked that 12 sets of a long-range microwave system be built. A magnetron producing 300 kW at 10.7 cm (2.8 GHz) was developed by the firm NEC. For radiating a narrow horizontal beam to sweep the sea surface, a slotted antenna 32 by 8 feet in size was designed by William H. Watson at McGill University. The system was designated "MEW/AS" ("Microwave Early Warning Anti Submarine").
Microwave
The development of radar, mainly in secrecy, before and during World War 2, resulted in the technological advances which made microwaves practical. Radar antennas small enough to fit on aircraft which had a narrow enough beamwidth to localize enemy aircraft required wavelengths in the centimeter range. It was found that conventional transmission lines used to carry radio waves had excessive power losses at microwave frequencies, and George Southworth at Bell Labs and Wilmer Barrow at MIT independently invented waveguide in 1936. Barrow invented the horn antenna in 1938 as a means to efficiently radiate microwaves into or out of a waveguide. In a microwave receiver, a nonlinear component was needed that would act as a detector and mixer at these frequencies, as vacuum tubes had too much capacitance. To fill this need researchers resurrected an obsolete technology, the point contact crystal detector (cat whisker detector) which was used as a demodulator in crystal radios around the turn of the century before vacuum tube receivers. The low capacitance of semiconductor junctions allowed them to function at microwave frequencies. The first modern silicon and germanium diodes were developed as microwave detectors in the 1930s, and the principles of semiconductor physics learned during their development led to semiconductor electronics after the war.
MCI Communications
MCI was founded as Microwave Communications, Inc. on October 3, 1963, with John D. Goeken being named the company's first president. The initial business plan was for the company to build a series of microwave relay stations between Chicago, Illinois, and St. Louis, Missouri. The relay stations would then be used to interface with limited-range two-way radios used by truckers along U.S. Route 66 or by barges on the Illinois Waterway. The long-distance communication service would then be marketed to shipping companies that were too small to build their own private relay systems. In addition to the radio relay services, MCI soon made plans to offer voice, computer information, and data communication services for business customers unable to afford AT&T's TELPAK service.
Horn antenna
One of the first horn antennas was constructed in 1897 by Bengali-Indian radio researcher Jagadish Chandra Bose in his pioneering experiments with microwaves. The modern horn antenna was invented independently in 1938 by Wilmer Barrow and G. C. Southworth The development of radar in World War 2 stimulated horn research to design feed horns for radar antennas. The corrugated horn invented by Kay in 1962 has become widely used as a feed horn for microwave antennas such as satellite dishes and radio telescopes.
Microwave oven
Studies have investigated the use of the microwave to clean non-metallic domestic sponges which have been thoroughly wetted. A 2006 study found that microwaving wet sponges for two minutes (at 1000 watt power) removed 99% of coliforms, "E. coli" and MS2 phages. "Bacillus cereus" spores were killed at four minutes of microwaving.
Microwave oven
Uneven heating in microwaved food can be partly due to the uneven distribution of microwave energy inside the oven, and partly due to the different rates of energy absorption in different parts of the food. The first problem is reduced by a stirrer, a type of fan that reflects microwave energy to different parts of the oven as it rotates, or by a turntable or carousel that turns the food; turntables, however, may still leave spots, such as the center of the oven, which receive uneven energy distribution. The location of dead spots and hot spots in a microwave can be mapped out by placing a damp piece of thermal paper in the oven. When the water saturated paper is subjected to the microwave radiation it becomes hot enough to cause the dye to be released which will provide a visual representation of the microwaves. If multiple layers of paper are constructed in the oven with a sufficient distance between them a three-dimensional map can be created. Many store receipts are printed on thermal paper which allows this to be easily done at home.
Edward George Bowen
Bowen went to the United States with the Tizard Mission in 1940 and helped to initiate tremendous advances in microwave radar as a weapon. Bowen visited US laboratories and told them about airborne radar and arranged demonstrations. He was able to take an early example of the cavity magnetron. With remarkable speed the US military set up a special laboratory, the MIT Radiation Laboratory for the development of centimetre-wave radar, and Bowen collaborated closely with them on their programme, writing the first draft specification for their first system. The first American experimental airborne 10 cm radar was tested, with Bowen on board, in March 1941, only seven months after the Tizard Mission had arrived.
Microwave sounding unit
The MSU was first launched aboard the TIROS-N satellite
in late 1978 and provided global coverage (from Pole to Pole). It carries a 4-channel microwave radiometer, operating between 50 and 60 GHz. Spatial resolution on the ground was 2.5 deg in longitude and latitude (about 250 km circle). There were 9 different MSUs launched; the most recent one on NOAA-14. They provided measurements of the temperature of the troposphere and lower stratosphere until 1998, when the first AMSU was deployed. AMSU provides many more channels and finer resolution (about 50 km).
Microwave oven
In the 1960s, Litton bought Studebaker's Franklin Manufacturing assets, which had been manufacturing magnetrons and building and selling microwave ovens similar to the Radarange. Litton then developed a new configuration of the microwave: the short, wide shape that is now common. The magnetron feed was also unique. This resulted in an oven that could survive a no-load condition: an empty microwave oven where there is nothing to absorb the microwaves. The new oven was shown at a trade show in Chicago, and helped begin a rapid growth of the market for home microwave ovens. Sales volume of 40,000 units for the U.S. industry in 1970 grew to one million by 1975. Market penetration was faster in Japan, due to a re-engineered magnetron allowing for less expensive units.
Several other companies joined in the market, and for a time most systems were built by defense contractors, who were most familiar with the magnetron. Litton was particularly well known in the restaurant business.