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  2. Hexbeam - Wikipedia

    en.wikipedia.org/wiki/Hexbeam

    A hexbeam, or hexagonal-beam, is a type of a directional antenna for shortwave, most often used in amateur radio. The name comes from the hexagonal outer shape of the antenna. It may also sometimes be known as a W-antenna, referring to the shape of the driver. The design looks something like an upturned umbrella.

  3. Directional antenna - Wikipedia

    en.wikipedia.org/wiki/Directional_antenna

    Patch antenna gain pattern. A directional antenna or beam antenna is an antenna which radiates or receives greater radio wave power in specific directions. Directional antennas can radiate radio waves in beams, when greater concentration of radiation in a certain direction is desired, or in receiving antennas receive radio waves from one specific direction only.

  4. Gain (antenna) - Wikipedia

    en.wikipedia.org/wiki/Gain_(antenna)

    In electromagnetics, an antenna's gain is a key performance parameter which combines the antenna's directivity and radiation efficiency. The term power gain has been deprecated by IEEE. [1] In a transmitting antenna, the gain describes how well the antenna converts input power into radio waves headed in a specified direction. In a receiving ...

  5. Optical parametric amplifier - Wikipedia

    en.wikipedia.org/wiki/Optical_parametric_amplifier

    The OPA will make the pump beam (ω p) weaker, and amplify the signal beam (ω s), and also create a new, so-called idler beam at the frequency ω i with ω p =ω s +ω i. In the OPA, the pump and idler photons usually travel collinearly through a nonlinear optical crystal. Phase matching is required for the process to work well.

  6. Semiconductor optical gain - Wikipedia

    en.wikipedia.org/wiki/Semiconductor_optical_gain

    Optical gain is the most important requirement for the realization of a semiconductor laser because it describes the optical amplification in the semiconductor material. This optical gain is due to stimulated emission associated with light emission created by recombination of electrons and holes.

  7. Squint (antenna) - Wikipedia

    en.wikipedia.org/wiki/Squint_(antenna)

    An example of squint caused by two differing frequencies. In a phased array or slotted waveguide antenna, squint refers to the angle that the transmission is offset from the normal of the plane of the antenna. In simple terms, it is the change in the beam direction as a function of operating frequency, polarization, or orientation. [1]

  8. Aperture (antenna) - Wikipedia

    en.wikipedia.org/wiki/Aperture_(antenna)

    The longer the effective length, the greater is the voltage appearing at its terminals. However, the actual power implied by that voltage depends on the antenna's feedpoint impedance, so this cannot be directly related to antenna gain, which is a measure of received power (but does not directly specify voltage or current). For instance, a half ...

  9. Amplifier figures of merit - Wikipedia

    en.wikipedia.org/wiki/Amplifier_figures_of_merit

    The use of voltage gain figure is appropriate when the amplifier's input impedance is much higher than the source impedance, and the load impedance higher than the amplifier's output impedance. If two equivalent amplifiers are being compared, the amplifier with higher gain settings would be more sensitive as it would take less input signal to ...