News tagged with microwave radiation
No extraordinary effects from microwave and mobile phone heating
The effect of microwave heating and cell phone radiation on sample material is no different than a temperature increase, according to scientists from the Department of Chemistry and Biochemistry, Arizona State University, ...
Nov 15, 2011 |
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New study shows cell phones exceed FCC exposure limits by as much as double for children
(Medical Xpress) -- A scholarly article on cell phone safety published online October 17, 2011, in the journal Electromagnetic Biology and Medicine reports the finding that cell phones used in the shirt or pants pocket exceed ...
Oct 17, 2011 |
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Researchers find world's first x-ray laser produces most coherent x-ray radiation ever
(PhysOrg.com) -- The world's first x-ray laser, the Linac Coherent Light Source (LCLS), first unveiled in 2009 at the Stanford Linear Accelerator Center in Palo Alto California, has been undergoing testing ...
Oct 03, 2011 |
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Mechanical micro-drum cooled to quantum ground state
Showcasing new tools for widespread development of quantum circuits made of mechanical parts, scientists from the National Institute of Standards and Technology have demonstrated a flexible, broadly usable ...
Jul 06, 2011 |
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Experts say cellphones are 'possibly carcinogenic'
(AP) -- A respected international panel of scientists says cellphones are possible cancer-causing agents, putting them in the same category as the pesticide DDT, gasoline engine exhaust and coffee.
May 31, 2011 |
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How do cell phones affect young brains?
Cell phone safety warnings are generally designed for a large man with a big head who talks less than half an hour a day.
Mar 18, 2011 |
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New approach to invisibility cloaking gets much closer to the science-fiction version
The idea of being able to become invisible, especially by simply covering up a person or an object with a special cloak, has a perennial appeal in science-fiction and fantasy literature. In recent years, researchers ...
Jan 25, 2011 |
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Astrophysicists discover new galaxy clusters revealed by cosmic 'shadows'
An international team of scientists led by Rutgers University astrophysicists have discovered 10 new massive galaxy clusters from a large, uniform survey of the southern sky. The survey was conducted using ...
Nov 01, 2010 |
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NIST ships first programmable AC/DC 10-volt standard
Extending its 26-year tradition of innovative quantum voltage standards, researchers at the National Institute of Standards and Technology (NIST) have begun shipping a new 10-volt standard to users around ...
Oct 27, 2010 |
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Ripples in the cosmic background
(PhysOrg.com) -- The universe was created 13.73 billion years ago in a blaze of light -- the big bang. We also think that, about 380,000 years later, after matter (mostly hydrogen atoms) had cooled enough ...
Sep 07, 2010 |
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New radiation mechanism may ward off cancer, oil spills and terrorism
Radiation similar to that used to treat cancer may someday help clean up environmental disasters such as the Gulf oil spill and detect explosive powder hidden underneath clothing.
Jul 15, 2010 |
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Planck satellite unveils the Universe -- now and then (w/ Video)
(PhysOrg.com) -- ESA's Planck mission has delivered its first all-sky image. It not only provides new insight into the way stars and galaxies form but also tells us how the Universe itself came to life after ...
Jul 05, 2010 |
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SMOS shines at symposium
Today, a focus at ESA's Living Planet Symposium is on the innovative SMOS mission, which recently became operational. Early results are proving very encouraging with its first observations due to be released in early July.
Space & Earth / Space Exploration
Jun 30, 2010 |
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Americans get most radiation from medical scans
(AP) -- We fret about airport scanners, power lines, cell phones and even microwaves. It's true that we get too much radiation. But it's not from those sources - it's from too many medical tests.
Jun 14, 2010 |
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Scientists create artificial mini 'black hole'
(PhysOrg.com) -- Scientists from China have built a device that can trap and absorb microwaves coming from all directions with a 99% absorption rate - a property that makes the device simulate, to some extent, ...
Jun 03, 2010 |
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Microwave
Microwaves are electromagnetic waves with wavelengths ranging from 1 m down to 1 mm, or equivalently, with frequencies between 0.3 GHz and 300 GHz.
Apparatus and techniques may be described qualitatively as "microwave" when the wavelengths of signals are roughly the same as the dimensions of the equipment, so that lumped-element circuit theory is inaccurate. As a consequence, practical microwave technique tends to move away from the discrete resistors, capacitors, and inductors used with lower frequency radio waves. Instead, distributed circuit elements and transmission-line theory are more useful methods for design and analysis. Open-wire and coaxial transmission lines give way to waveguides, and lumped-element tuned circuits are replaced by cavity resonators or resonant lines. Effects of reflection, polarization, scattering, diffraction and atmospheric absorption usually associated with visible light are of practical significance in the study of microwave propagation. The same equations of electromagnetic theory apply at all frequencies.
While the name may suggest a micrometer wavelength, it is better understood as indicating wavelengths very much smaller than those used in radio broadcasting. The boundaries between far infrared light, terahertz radiation, microwaves, and ultra-high-frequency radio waves are fairly arbitrary and are used variously between different fields of study. The term microwave generally refers to "alternating current signals with frequencies between 0.3 GHz (3×108 Hz) and 300 GHz (3×1011 Hz)." Both IEC standard 60050 and IEEE standard 100 define "microwave" frequencies starting at 1 GHz (30 cm wavelength).
Electromagnetic waves longer (lower frequency) than microwaves are called "radio waves". Electromagnetic radiation with shorter wavelengths may be called "millimeter waves", terahertz radiation or even T-rays. Definitions differ for millimeter wave band, which the IEEE defines as 110 GHz to 300 GHz.
For more information about Microwave, read the full article at
Wikipedia.
This text uses material from Wikipedia and is available under the GNU Free Documentation License.
