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In radio and telecommunication, a traveling-wave antenna is a class of antenna that uses a traveling wave on a guiding structure as the main radiating mechanism. Its distinguishing feature is that the radio-frequency current that generates the radio waves travels through the antenna in one direction.
The second antenna is a reference antenna, which points rigidly at the first antenna. Each antenna is alternately connected to a transmitter having a particular source impedance, and a receiver having the same input impedance (the impedance may differ between the two antennas).
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 ...
The quarter-wave monopole, the most compact resonant antenna, may be the most widely used antenna in the world. The five-eighth wave monopole – length 0.625 λ, or 5 / 8 of a wavelength – is also popular, since at that length monopoles direct the greatest proportion of their radiated power horizontally, hence the best use of ...
In antenna engineering, sidelobes are the lobes (local maxima) of the far field radiation pattern of an antenna or other radiation source, that are not the main lobe.. The radiation pattern of most antennas shows a pattern of "lobes" at various angles, directions where the radiated signal strength reaches a maximum, separated by "nulls", angles at which the radiated signal strength falls to zero.
Electromagnetic waves are radiated by electric charges when they are accelerated. [2] [10] In a transmitting antenna, radio waves are generated by time varying electric currents, consisting of electrons accelerating as they flow back and forth in the metal antenna, driven by the electric field due to the oscillating voltage applied to the antenna by the radio transmitter.
A "Beverage on the ground" – often called a "B.O.G." or bog antenna – is a "snake antenna" laid in a straight line that has its end opposite the feedpoint grounded. It is a travelling wave antenna, and might technically be considered an extreme instance of a low-hanging Beverage antenna. [citation needed]
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]