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  2. Free-space path loss - Wikipedia

    en.wikipedia.org/wiki/Free-space_path_loss

    The radio waves from the transmitting antenna spread out in a spherical wavefront. The amount of power passing through any sphere centered on the transmitting antenna is equal. The surface area of a sphere of radius is . Thus the intensity or power density of the radiation in any particular direction from the antenna is inversely proportional ...

  3. Antenna measurement - Wikipedia

    en.wikipedia.org/wiki/Antenna_measurement

    Typical antenna parameters are gain, bandwidth, radiation pattern, beamwidth, polarization, impedance; These are imperative communicative means. The antenna pattern is the response of the antenna to a plane wave incident from a given direction or the relative power density of the wave transmitted by the antenna in a given direction. For a ...

  4. Wavefront - Wikipedia

    en.wikipedia.org/wiki/Wavefront

    The plane wavefront is a good model for a surface-section of a very large spherical wavefront; for instance, sunlight strikes the earth with a spherical wavefront that has a radius of about 150 million kilometers (1 AU). For many purposes, such a wavefront can be considered planar over distances of the diameter of Earth.

  5. Huygens–Fresnel principle - Wikipedia

    en.wikipedia.org/wiki/Huygens–Fresnel_principle

    The Huygens–Fresnel principle (named after Dutch physicist Christiaan Huygens and French physicist Augustin-Jean Fresnel) states that every point on a wavefront is itself the source of spherical wavelets, and the secondary wavelets emanating from different points mutually interfere. [1] The sum of these spherical wavelets forms a new wavefront.

  6. Ray tracing (physics) - Wikipedia

    en.wikipedia.org/wiki/Ray_tracing_(physics)

    Ray tracing of a beam of light passing through a medium with changing refractive index.The ray is advanced by a small amount, and then the direction is re-calculated. Ray tracing works by assuming that the particle or wave can be modeled as a large number of very narrow beams (), and that there exists some distance, possibly very small, over which such a ray is locally straight.

  7. Passive electronically scanned array - Wikipedia

    en.wikipedia.org/wiki/Passive_electronically...

    The individual wavefronts are spherical, but they combine in front of the antenna to create a plane wave, a beam of radio waves travelling in a specific direction θ. The phase shifters delay the radio waves progressively going up the line so each antenna emits its wavefront later than the one below it.

  8. Plane-wave expansion - Wikipedia

    en.wikipedia.org/wiki/Plane-wave_expansion

    In physics, the plane-wave expansion expresses a plane wave as a linear combination of spherical waves: = = (+) (^ ^), where i is the imaginary unit , k is a wave vector of length k ,

  9. Phased array - Wikipedia

    en.wikipedia.org/wiki/Phased_array

    The individual wavefronts are spherical, but they combine in front of the antenna to create a plane wave. The phase shifters delay the radio waves progressively going up the line so each antenna emits its wavefront later than the one below it. This causes the resulting plane wave to be directed at an angle θ to the