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  2. Wavelength - Wikipedia

    en.wikipedia.org/wiki/Wavelength

    The wavelength of a sine wave, λ, can be measured between any two points with the same phase, such as between crests (on top), or troughs (on bottom), or corresponding zero crossings as shown. In physics and mathematics, wavelength or spatial period of a wave or periodic function is the distance over which the wave's shape repeats.

  3. Illumination efficiency - Wikipedia

    en.wikipedia.org/wiki/Illumination_efficiency

    and under effective area of an antenna, IEEE states, "The effective area of an antenna in a given direction is equal to the square of the operating wavelength times its gain in that direction divided by 4π." Gain is also defined to be less than directivity by the radiation efficiency, [1]

  4. Radio wave - Wikipedia

    en.wikipedia.org/wiki/Radio_wave

    The wavelength is the distance from one peak (crest) of the wave's electric field to the next, and is inversely proportional to the frequency of the wave. The relation of frequency and wavelength in a radio wave traveling in vacuum or air is = , where

  5. Wavelength-division multiplexing - Wikipedia

    en.wikipedia.org/wiki/Wavelength-division...

    WDM operating principle WDM System in rack 19/21'' A WDM system uses a multiplexer at the transmitter to join the several signals together and a demultiplexer at the receiver to split them apart. [1] With the right type of fiber, it is possible to have a device that does both simultaneously and can function as an optical add-drop multiplexer.

  6. Microwave - Wikipedia

    en.wikipedia.org/wiki/Microwave

    The short wavelength of microwaves causes large reflections from objects the size of motor vehicles, ships and aircraft. Also, at these wavelengths, the high gain antennas such as parabolic antennas which are required to produce the narrow beamwidths needed to accurately locate objects are conveniently small, allowing them to be rapidly turned ...

  7. Waveguide (radio frequency) - Wikipedia

    en.wikipedia.org/wiki/Waveguide_(radio_frequency)

    In radio-frequency engineering and communications engineering, a waveguide is a hollow metal pipe used to carry radio waves. [1] This type of waveguide is used as a transmission line mostly at microwave frequencies, for such purposes as connecting microwave transmitters and receivers to their antennas, in equipment such as microwave ovens, radar sets, satellite communications, and microwave ...

  8. Electromagnetic spectrum - Wikipedia

    en.wikipedia.org/wiki/Electromagnetic_spectrum

    Longer-wavelength radiation such as visible light is nonionizing; the photons do not have sufficient energy to ionize atoms. Throughout most of the electromagnetic spectrum, spectroscopy can be used to separate waves of different frequencies, so that the intensity of the radiation can be measured as a function of frequency or wavelength.

  9. Ultra high frequency - Wikipedia

    en.wikipedia.org/wiki/Ultra_high_frequency

    Ultra high frequency (UHF) is the ITU designation [1] [2] for radio frequencies in the range between 300 megahertz (MHz) and 3 gigahertz (GHz), also known as the decimetre band as the wavelengths range from one meter to one tenth of a meter (one decimeter).