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File:Dipole antenna standing waves animation 1-10fps.gif

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Dipole_antenna_standing_waves_animation_1-10fps.gif(682 × 311 pixels, file size: 170 KB, MIME type: image/gif, looped, 20 frames, 2.0 s)


English: Animation showing standing waves on a half-wave dipole antenna driven by a sinusoidal voltage VO from a radio transmitter at its resonant frequency. The oscillating voltage pushes the electrons back and forth along the two metal rods that make up the antenna, creating oscillating currents (blue arrows) in the antenna, charging its ends alternately positive (+) and negative (-). Since at this frequency the antenna is a half wavelength (λ/2) long, a sinusoidal wave of voltage or current takes exactly one cycle to make the round trip from one end of the antenna to the other and back, so the reflected waves reinforce each other. The antenna acts like an electronic resonater. Waves of current and voltage reflecting back and forth between the ends of the rods interfere to form standing waves. The waves are shown graphically by bars of color (red for voltage V(x) and blue for current I(x)) whose width at each point is proportional to the amplitude of the wave at that point. There are voltage antinodes (maxima) and current nodes (zero points) at each end, where positive (+) and negative (−) charges accumulate alternately each half cycle, while there is a voltage node and current antinode at the drive point in the center. The large oscillating voltages and currents on the antenna at resonance causes it to radiate maximum radio wave power.
Source Own work
Author Chetvorno


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Animation showing standing waves of voltage and current on a dipole antenna

6 June 2015

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current05:00, 9 July 2020Thumbnail for version as of 05:00, 9 July 2020682 × 311 (170 KB)ChetvornoImproved current arrows, made motion less jerky, added plus and minus charges in antenna
11:00, 6 June 2015Thumbnail for version as of 11:00, 6 June 2015461 × 217 (88 KB)ChetvornoUser created page with UploadWizard
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