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  2. Dipole antenna - Wikipedia

    en.wikipedia.org/wiki/Dipole_antenna

    German physicist Heinrich Hertz first demonstrated the existence of radio waves in 1887 using what we now know as a dipole antenna (with capacitative end-loading). On the other hand, Guglielmo Marconi empirically found that he could just ground the transmitter (or one side of a transmission line, if used) dispensing with one half of the antenna, thus realizing the vertical or monopole antenna.

  3. Coaxial antenna - Wikipedia

    en.wikipedia.org/wiki/Coaxial_antenna

    A coaxial antenna (often known as a coaxial dipole) is a particular form of a half-wave dipole antenna, most often employed as a vertically polarized omnidirectional antenna. History [ edit ]

  4. Retarded potential - Wikipedia

    en.wikipedia.org/wiki/Retarded_potential

    Position vectors r and r′ used in the calculation. The starting point is Maxwell's equations in the potential formulation using the Lorenz gauge: =, = where φ(r, t) is the electric potential and A(r, t) is the magnetic vector potential, for an arbitrary source of charge density ρ(r, t) and current density J(r, t), and is the D'Alembert operator. [2]

  5. Radiation resistance - Wikipedia

    en.wikipedia.org/wiki/Radiation_resistance

    When the antenna is fed at a point of maximum current, as in the common center-fed half-wave dipole or base-fed quarter-wave monopole, that value is mostly the radiation resistance. However, if the antenna is fed at some other point, the equivalent radiation resistance at that point R r a d 1 {\displaystyle \ R_{\mathsf {rad\ 1}}\ } can easily ...

  6. Log-periodic antenna - Wikipedia

    en.wikipedia.org/wiki/Log-periodic_antenna

    The most common form of log-periodic antenna is the log-periodic dipole array or LPDA, The LPDA consists of a number of half-wave dipole driven elements of gradually increasing length, each consisting of a pair of metal rods.

  7. Radio wave - Wikipedia

    en.wikipedia.org/wiki/Radio_wave

    Animation of a half-wave dipole antenna radiating radio waves, showing the electric field lines. The antenna in the center is two vertical metal rods connected to a radio transmitter (not shown). The transmitter applies an alternating electric current to the rods, which charges them alternately positive (+) and negative (−).

  8. Yagi–Uda antenna - Wikipedia

    en.wikipedia.org/wiki/Yagi–Uda_antenna

    A Yagi–Uda antenna, or simply Yagi antenna, is a directional antenna consisting of two or more parallel resonant antenna elements in an end-fire array; [1] these elements are most often metal rods (or discs) acting as half-wave dipoles. [2] Yagi–Uda antennas consist of a single driven element connected to a radio transmitter or receiver (or ...

  9. Antenna (radio) - Wikipedia

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

    The monopole antenna is essentially one half of the half-wave dipole, a single ⁠ 1 / 4 ⁠ wavelength element with the other side connected to ground or an equivalent ground plane (or counterpoise). Monopoles, which are one-half the size of a dipole, are common for long-wavelength radio signals where a dipole would be impractically large.