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Topic: Microwave power transmission


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In the News (Sat 19 Dec 09)

  
  Microwave power transmission - Wikipedia, the free encyclopedia
Microwave power transmission (MPT) is the use of microwaves to transmit power through outer space or the atmosphere without the need for wires.
Using microwave power transmission to deliver electricity to communities without having to build cable-based infrastructure is being studied at Grand Bassin on Reunion Island in the Indian Ocean.
The common reaction to microwave transmission is one of concern, as microwaves are generally perceived by the public as dangerous forms of radiation - stemming from the fact that they are used in microwave ovens.
en.wikipedia.org /wiki/Microwave_power_transmission   (454 words)

  
 Microwave Transmission. The History of Microwave Power Transmission.
The reason for a lack of interest in radio power transmission in the first half of this century is clear.
People were waiting for the invention of a high-power microwave device to generate electromagnetic energy of reasonably short wavelength, since efficient focusing toward the power-receiving destination is strongly dependent on the use of technology of narrow-beam formation by small-size antennas and reflectors.
Microwave generation by the klystron was achieved by the Varian brothers in 1937 based on the first idea by the Heil brothers in Germany in 1935.
www.microwavecooking.com /Microwave_Transmission.htm   (653 words)

  
 Low Loss Sapphire Windows for High Power Microwave Transmission
Thermal loading of a microwave window is different from the usual application where the heating is external, because the heat is deposited throughout the bulk of the window, primarily at its center where the radial maxima of the electric field occurs for the primary microwave modes (e.g.
As both microwave power and frequency (window absorption increases with frequency at room temperature) have increased, standard sapphire windows have reached their limits and are currently a major constraint on the development of high power microwave systems.
Power was fed into the input port using a TE mode transducer from standard rectangular waveguide (WR-15 for the 50-75 GHz band) and a gradual diameter taper to large diameter for high mode purity.
www.tvu.com /PLowLossSWinweb.htm   (20546 words)

  
 Microwave transmission - Wikipedia, the free encyclopedia
Atmospheric attenuation of microwaves in dry air with a precipitable water vapor level of 0.001 mm.
Microwave transmission refers to the technique of transmitting information over a Microwave link.
Since microwaves are highly susceptible to attenuation by the atmosphere (especially during wet weather), the use of microwave transmission is limited to a few contexts.
en.wikipedia.org /wiki/Microwave_transmission   (142 words)

  
 Microwave Information - microwave ovens
Microwaves can be generated by a variety of means, generally divided into two categories: solid microwave ovens state microwave microwave antenna orientation convection oven devices and vacuum-tube based devices.
microwave power transmission Vacuum tube based devices operate on the ballistic motion of electrons in a vacuum under the microwave oven influence of controlling electric sharp microwave ovens or magnetic fields, and include the magnetron, klystron, travelling wave tube (TWT), and gyrotron.
Typically, microwaves are used in television news to transmit a signal from a remote location to a television station from a specially equipped van.
www.inanot.com /Ina-Electronics_Topics_Me_-_N-/Microwave.html   (1006 words)

  
 History of Microwave Power Transmission before 1980y   (Site not responding. Last check: 2007-10-13)
The post-war history of research on free-space power transmission is well documented by Willian C. Brown, who was a pioneer of practical microwave power transmission.
A power conversion device from microwave to DC, called a rectenna, was invented and used for the microwave-powered helicopter.
The highest record of 84 % efficiency was attained in the demonstration of microwave power transmission in 1975 at the JPL Goldstone Facility.
www.kurasc.kyoto-u.ac.jp /plasma-group/sps/history2-e.html   (389 words)

  
 Microwave
Microwaves are a form of electromagnetic radiation with frequencies ranging from several hundred MHz to several hundred GHz and wavelengths ranging from approximately 1 to 20 centimeters.
Because of their high frequencies, microwaves have the advantage of being able to carry more information than ordinary radio waves and are capable of being beamed directly from one point to another.
Microwave also introduced the possibility for CATV operators to select which broadcast signals they would carry, sometimes allowing them to bypass closer signals in order to provide their customers with more desirable programming--perhaps from well-funded stations in large cities.
www.museum.tv /archives/etv/M/htmlM/microwave/microwave.htm   (601 words)

  
 Microwave Cooking. Microwave cooking recipes and links to other microwave related information.
Microwave cooking recipes and links to other microwave related information.
Microwave Experiments - Four experiments that can be performed using any microwave oven, including; marshmallow, compact disk, wire wool and light bulb.
Microwave Power Amplifiers - Microwave power amplifiers can be divided into CW Amplifiers and Pulsed Amplifiers depending upon their application.
www.microwavecooking.com   (913 words)

  
 Testimony of John Mankins
Although there is no evidence of negative environmental impacts from either microwave or visible light approaches to wireless power transmission at the power intensities considered by NASA’s recent SSP studies, environmental and safety factors continue to be given careful consideration.
Substantial demonstrations of power beaming from ground-to-space might also be achievable during the next decade (for example, to transmit power to an electric orbital transfer vehicle operating in Earth orbit).
However, using current concepts for a geostationary Earth-orbit-based relay, a microwave wireless power transmission system is expected to be either too large on the ground (or in space) to be viable.
www.hq.nasa.gov /office/legaff/mankins9-7.html   (4328 words)

  
 [No title]   (Site not responding. Last check: 2007-10-13)
The microwave power transmission is a unique, epoch-making and the best method for human being to obtain absolute clean energy, when it will be used to transmit electricity from the future power station in the space to the earth.
Applying the microwave power transmission technology to drive agricultural vehicles, an ideal vehicle can be designed and developed, that has no emission, no heavy battery, is small and light, with low energy consumption and flexible form.
The microwave was generated by a magnetron, transmitted from a horn-antenna and received by a rectifying antenna.
www.crrel.usace.army.mil /confs/ISTVS/Abstracts/Oida.doc   (184 words)

  
 Lunar Solar Power Generation
In both scenarios, power can be supplied to the rectenna at night Several thousand individual rectennas strategically located around the globe, with a total area of 100,000 km2, could continuously provide the 20 TW of electric power, or 2 kW per person, required for a prosperous world of 10 billion people in 2050.
For direct microwave wireless power transmission to the surface of the earth, a limited range of transmission frequencies is suitable.
Transmission efficiency çb for Gaussian beams is related to the aperture sizes of the transmitting and receiving antennas: çb ~ 1- exp (-ô2) and ô = ðDtDr/ (4ëR) Where Dt is the transmitting array diameter, Dr is the receiving array diameter, çb.is the wavelength of transmission and R is the range of transmission.
www.acm.org /ubiquity/views/v7i28_kumar.html   (2700 words)

  
 Entropy Production: Solar Power Satellite
One oft repeated concept in science fiction is that of power being generated in space by solar cells and then beamed down to the surface.
While microwave transmission is quite efficient on the emission and reception ends there will be some loss in the atmosphere.
It will be able to redirect the largest amount of power during the middle of the night when it is on the far side of the earth from the sun and no power at noon.
entropyproduction.blogspot.com /2006/07/solar-power-satellite.html   (3067 words)

  
 SHARP   (Site not responding. Last check: 2007-10-13)
Microwave power would be transmitted from a large ground antenna system to a circling airplane.
The DC power would be used to drive electric motors on the airplane for propulsion, to power the payload and control systems and to charge standby energy storage units.
To provide the necessary microwave power, a low-power ground station was designed and constructed at CRC under the direction of Joe Schlesak.
www.friendsofcrc.ca /Projects/SHARP/sharp.html   (1727 words)

  
 Demonstration of Wireless Power Transmission   (Site not responding. Last check: 2007-10-13)
William C. Brown, the leading authority on wireless power transmission technology, has loaned this demonstration unit to the Texas Space Grant Consortium to show how power can be transfered through free space by microwaves.
The microwave source consists of a microwave oven magnetron with electronics to control the output power.
The output microwave power ranges from 50 W to 200 W at 2.45 GHz.
www.tsgc.utexas.edu /tadp/1996/general/wpt.html   (308 words)

  
 LiftPort Group Discussion Boards - Economics of Solar Power Satellites   (Site not responding. Last check: 2007-10-13)
Even if we wanted to power the SE with an SPS, the ground antenna array for reception of a significant amount of microwave power (from the SPS) would be much too large to fit on the platform.
Microwave Power Transmission (MPT) technology is one of the most essential parts for Solar Power Station/Satellite (SPS).
Modern solid state microwave sources typically operate around 25 to 30%, and are used primarily because they can generate a wide range of frequencies.
www.liftport.com /forums/showthread.php?p=3827   (2541 words)

  
 Statement to
Other applications include beamed power to communications and information-gathering stations on planetary surfaces or in orbit; e.g., high-power radar mappers; mobile robotic systems; remote sensing stations; dispersed habitation modules; human-occupied field stations; and supplementary power to surface solar power systems during periods when they are shadowed.
To resolve these and other wireless power transmission issues, a test and verification facility is needed to develop techniques and make actual measurements of the various spectrum sidelobe and grating lobe levels from a large power-transmitting phased array.
In the case of microwaves, the diffraction due to the low frequency of the power beam would require enormous receiving antennas or reflectors in orbit.
www.house.gov /science/grey_090700.htm   (5605 words)

  
 Microwave Battery Charger   (Site not responding. Last check: 2007-10-13)
The umbilical cable that supplies power to a spacecraft on a launch pad must be disconnected at some prescribed time before launch.
The microwave beam from this source would be aimed at the spacecraft through a microwave-transparent window on the fairing of the launch rocket.
A rectifier-and-power-converter circuit connected to the antenna would convert the received microwave power to dc power, which would be used to charge the spacecraft batteries.
www.nasatech.com /Briefs/Apr00/GSC13784.html   (254 words)

  
 Inverse Rectennas for Two-Way Wireless Power Transmission   (Site not responding. Last check: 2007-10-13)
Heretofore, a bidirectional microwave terminal for a typical conceptual wireless-power-transmission system might have included (a) a transmitter comprising a transmitting antenna connected to a magnetron or klystron oscillator or perhaps an impact avalanche transit-time- (IMPATT)-diode oscillator, plus (b) a receiver comprising a separate rectenna.
If only one device — a rectenna capable of operating in transmitting as well as receiving mode — could be used at each end of a microwave power link, then the cost of the link could be reduced.
Potential applications for inverse rectennas lie in the microwave wireless transmission of power between any two of the following: ground stations, airships, aircraft, and spacecraft.
www.nasatech.com /Briefs/July98/NPO20321.html   (459 words)

  
 Solar power satellites (Dani Eder; Henry Spencer; Jordin Kare)
From: ederd@bcstec.ca.boeing.com (Dani Eder) Subject: Re: Microwave power transmission (was Re: ENVIRON-NUTS) Date: Sep 19 1995 Newsgroups: sci.energy Rod Adams writes: >Paul, one of the Florida utilities has a power generation capacity of >14,000 MWe.
To maintain high efficiency, the power satellite concepts included thermal annealing of the arrays periodically to remove the cell defects generated by radiation.
However, the most obvious one is that cloud cover will scatter any radiation short enough to allow practical transmission from GEO to meter-scale collectors (assuming the transmitting aperture is not 100+ km across), which pretty much rules out short wavelengths (infrared or visible light) for direct transmission of power from space to distributed ground receivers.
www.yarchive.net /space/spacecraft/solar_power_satellites.html   (3761 words)

  
 Will power transmission without wires ever be possible? - Bad Astronomy and Universe Today Forum   (Site not responding. Last check: 2007-10-13)
When I was young I made a radio set that used the energy of the radio waves to power the earphone, so I know that there is energy in the air all the time.
There also were ideas for orbital microwave "reflectors." One problem with a microwave system is that it would probably require a very large transmission and reception area, so there also was consideration of laser transmission and reception, but there are serious efficiency issues.
The power station does something to their particles and the particles at home follow suit and energy gets transferred.
www.bautforum.com /showthread.php?p=867361#post867361   (1831 words)

  
 High Power Converter of Microwaves into DC
For many types of wireless power transmission (WPT) systems, diode-type rectenna (rectify antenna) [1,2] is the best (and the simplest) device for back-conversion of microwaves into D.C. Diode-type rectennas have played and play a fundamental role at the stage of principal demonstration of the possibilities of high efficient wireless power transmission by microwaves.
This is a well-known physical result: all power is transmitted from the external generator into the load when their conductivities are matched in a complex-conjugated way, i.e.
However is also applicable to many other occasions where microwave power transmissions of high density of electric power is necessary, such as non contact wireless power transmission in factories and for power feeding to electric vehicles.
jre.cplire.ru /jre/sep99/1/text.html   (1883 words)

  
 Magnetic Fields & Radio Frequency
Radiofrequency (RF) and microwave (MW) radiation are electromagnetic radiation in the frequency ranges 3 kilohertz (kHz) - 300 Megahertz (MHz), and 300 MHz - 300 gigahertz (GHz), respectively.
Microwave radiation is absorbed near the skin, whereas RF radiation may be absorbed in deep body organs.
Exposure to the very high intensity electromagnetic fields found in the immediate vicinity of certain sources such as radar installations and TV or radio transmitters can produce electrical shock or a variety of heating effects, which may range from a sensation of warmth to burns and eventual cataract formation.
www.brown.edu /Administration/EHS/radiation/rf.htm   (322 words)

  
 ESA - GSP - Science and Exploration98/S40 detail
The collection of solar energy in space and the subsequent microwave transmission to Earth is one proposed option, involving Solar Power Satellites (SPS) which feature very large structures with photovoltaic cells in space.
Complementary, Power Relay Satellites (PRS) could be employed to transmit energy produced, for example, by TPPs located in regions of high insolation, such as deserts.
This is mostly due to the fact that terrestrial competitors for power generation including regenerative options significantly affect the affordability and justification of SSP.
www.esa.int /SPECIALS/GSP/SEMTG70P4HD_0.html   (3242 words)

  
 Electrostatic-Accelerator Free Electron Masers   (Site not responding. Last check: 2007-10-13)
The concept and schemes of microwave power transmission through the atmosphere were proposed and developed by Brown.
Realization of this concept for microwave power beaming with practical antennas to an unmanned aerial vehicle (UAV) flying at an altitude of 20 km (this sltitude is most fitting for commercial applications, such as communication) becomes possible by use of millimeter waves for power beaming.
Millimeter wave gyrotrons operating at 200 kW CW power are commercially available, and at the present time would probably be a preferable choice for moderate power transmission applications.
www.eng.tau.ac.il /research/FEL/0b0.html   (616 words)

  
 L5 News: Laser SPS and the Hydrogen Economy
Under this and previous conventions, radio and microwave frequencies are allocated by ITU and ITU is also responsible for preventing broadcast interference.
Since the SPS has a power transmission function, the question of ITU jurisdiction must be settled internationally.
The use of laser instead of microwaves for power transmission has a dramatic impact on the overall acceptability of the SPS.
www.nss.org /settlement/L5news/1980-hydrogen.htm   (2682 words)

  
 The 1996 IEEE MTT Conference
The founding father of modern microwave power transmission gave a presentation and showed videos of the microwave-powered helicopter that he built for the Air Force in the 1970's which was also funded by Raytheon.
There are several medical applications, mainly to treat tumors by focusing high power microwaves on them (hyperthermia treatment).
The problem stems from the fact that many high-frequency devices have inherent non-linearities and this is especially a problem at higher microwave power.
www.media.mit.edu /physics/trips/microwave-96/conference.html   (1587 words)

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