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  2. Radiation-absorbent material - Wikipedia

    en.wikipedia.org/wiki/Radiation-absorbent_material

    With each bounce, the wave loses energy to the foam material and thus exits with lower signal strength. [1] An alternative type of RAM comprises flat plates of ferrite material, in the form of flat tiles fixed to all interior surfaces of the chamber. This type has a smaller effective frequency range than the pyramidal RAM and is designed to be ...

  3. Absorption (electromagnetic radiation) - Wikipedia

    en.wikipedia.org/wiki/Absorption_(electromagnetic...

    In physics, the D-region of Earth's ionosphere is known to significantly absorb radio signals that fall within the high-frequency electromagnetic spectrum. In nuclear physics, absorption of nuclear radiations can be used for measuring the fluid levels, densitometry or thickness measurements. [2]

  4. Electromagnetic radiation - Wikipedia

    en.wikipedia.org/wiki/Electromagnetic_radiation

    EMR of lower energy ultraviolet or lower frequencies (i.e., near ultraviolet, visible light, infrared, microwaves, and radio waves) is non-ionizing because its photons do not individually have enough energy to ionize atoms or molecules or to break chemical bonds. The effect of non-ionizing radiation on chemical systems and living tissue is ...

  5. Radio wave - Wikipedia

    en.wikipedia.org/wiki/Radio_wave

    VLF and ELF radio waves can also penetrate water to hundreds of meters deep, so they are used to communicate with submerged submarines. Skywaves: At medium wave and shortwave wavelengths, radio waves reflect off conductive layers of charged particles in a part of the atmosphere called the ionosphere. So radio waves directed at an angle into the ...

  6. Electromagnetic spectrum - Wikipedia

    en.wikipedia.org/wiki/Electromagnetic_spectrum

    Radio waves, at the low-frequency end of the spectrum, have the lowest photon energy and the longest wavelengths—thousands of kilometers, or more. They can be emitted and received by antennas , and pass through the atmosphere, foliage, and most building materials.

  7. Radio propagation - Wikipedia

    en.wikipedia.org/wiki/Radio_propagation

    Radio propagation is the behavior of radio waves as they travel, or are propagated, from one point to another in vacuum, or into various parts of the atmosphere. [1]: 26‑1 As a form of electromagnetic radiation, like light waves, radio waves are affected by the phenomena of reflection, refraction, diffraction, absorption, polarization, and scattering. [2]

  8. Low emissivity - Wikipedia

    en.wikipedia.org/wiki/Low_emissivity

    Low emissivity (low e or low thermal emissivity) refers to a surface condition that emits low levels of radiant thermal (heat) energy. All materials absorb, reflect, and emit radiant energy according to Planck's law but here, the primary concern is a special wavelength interval of radiant energy, namely thermal radiation of materials.

  9. Radio map - Wikipedia

    en.wikipedia.org/wiki/Radio_map

    Example of a radio map estimate using STORM, a transformer-based radio map estimator. Signal strength maps quantify signal strength at each location. Formally, a signal strength map can be seen as a function γ ( r ) {\displaystyle \gamma (\mathbf {r} )} that provides a signal strength metric for each location r {\displaystyle \mathbf {r} } .