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  2. Distributed Bragg reflector - Wikipedia

    en.wikipedia.org/wiki/Distributed_Bragg_reflector

    Time-resolved simulation of a pulse reflecting from a Bragg mirror. A distributed Bragg reflector (DBR) is a reflector used in waveguides, such as optical fibers.It is a structure formed from multiple layers of alternating materials with different refractive index, or by periodic variation of some characteristic (such as height) of a dielectric waveguide, resulting in periodic variation in the ...

  3. Quarter-wave impedance transformer - Wikipedia

    en.wikipedia.org/wiki/Quarter-wave_impedance...

    The quarter wave transformer is an alternative to a stub; but, whereas a stub is terminated in a short (or open) circuit and the length is chosen so as to produce the required impedance transformation, the λ/4 transformer is in series with the load and its length and characteristic impedance are designed to produce the required impedance ...

  4. Waveplate - Wikipedia

    en.wikipedia.org/wiki/Waveplate

    Two waves differing by a quarter-phase shift for one axis Creating circular polarization using a quarter-wave plate and a polarizing filter. For a quarter-wave plate, the relationship between L, Δn, and λ 0 is chosen so that the phase shift between polarization components is Γ = π/2. Now suppose a linearly polarized wave is incident on the ...

  5. Antenna (radio) - Wikipedia

    en.wikipedia.org/wiki/Antenna_(radio)

    The definition of antenna gain or power gain already includes the effect of the antenna's efficiency. Therefore, if one is trying to radiate a signal toward a receiver using a transmitter of a given power, one need only compare the gain of various antennas rather than considering the efficiency as well.

  6. Anti-reflective coating - Wikipedia

    en.wikipedia.org/wiki/Anti-reflective_coating

    In the calculation of the reflection from a stack of layers, the transfer-matrix method can be used. Interference in a quarter-wave anti-reflection coating. Real coatings do not reach perfect performance, though they are capable of reducing a surface reflection coefficient to less than 0.1%.

  7. Collinear antenna array - Wikipedia

    en.wikipedia.org/wiki/Collinear_antenna_array

    Collinear dipole array on repeater for radio station JOHG-FM on Mt. Shibisan, Kagoshima, Japan. In telecommunications, a collinear antenna array (sometimes spelled colinear antenna array) is an array of dipole or quarter-wave antennas mounted in such a manner that the corresponding elements of each antenna are parallel and collinear; that is, they are located along a common axis.

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  9. Optical coating - Wikipedia

    en.wikipedia.org/wiki/Optical_coating

    This periodic system significantly enhances the reflectivity of the surface in the certain wavelength range called band-stop, whose width is determined by the ratio of the two used indices only (for quarter-wave systems), while the maximum reflectivity increases up to almost 100% with a number of layers in the stack.