What is Antenna: Definition and 414 Discussions

In radio engineering, an antenna or aerial is the interface between radio waves propagating through space and electric currents moving in metal conductors, used with a transmitter or receiver. In transmission, a radio transmitter supplies an electric current to the antenna's terminals, and the antenna radiates the energy from the current as electromagnetic waves (radio waves). In reception, an antenna intercepts some of the power of a radio wave in order to produce an electric current at its terminals, that is applied to a receiver to be amplified. Antennas are essential components of all radio equipment.
An antenna is an array of conductors (elements), electrically connected to the receiver or transmitter. Antennas can be designed to transmit and receive radio waves in all horizontal directions equally (omnidirectional antennas), or preferentially in a particular direction (directional, or high-gain, or “beam” antennas). An antenna may include components not connected to the transmitter, parabolic reflectors, horns, or parasitic elements, which serve to direct the radio waves into a beam or other desired radiation pattern.
The first antennas were built in 1888 by German physicist Heinrich Hertz in his pioneering experiments to prove the existence of waves predicted by the electromagnetic theory of James Clerk Maxwell. Hertz placed dipole antennas at the focal point of parabolic reflectors for both transmitting and receiving. Starting in 1895, Guglielmo Marconi began development of antennas practical for long-distance, wireless telegraphy, for which he received a Nobel Prize.

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  1. qnach

    Is there an antenna with this shape?

    Is there an antenna of S shape or perhaps a butterfly shape? What is the benefit of such design?
  2. qnach

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  3. qnach

    I Original references for Hertz's experiments

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  4. qnach

    I Non-conductor made antenna?

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  5. N

    How to compute the location of the antenna when I rotate it?

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  6. S

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  7. Tone L

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  8. M

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  9. P

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  10. N

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  11. physicsEnthu_123

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  12. GhostLoveScore

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  13. M

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  14. T

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  15. V

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  16. A

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  17. T

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  18. Bishamonten

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  19. R

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  20. D

    Could capacitors function as antennas?

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  21. P

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  22. M

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  23. Spinnor

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  25. M

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  26. O

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  27. M

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  31. S

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  32. TheSodesa

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  33. M

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  34. S

    Why do we want high Radiation Resistance in an antenna?

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  35. T

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  36. H

    Free online antenna design software?

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  37. loki4000

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  38. C

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  39. GhostLoveScore

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  40. J

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  41. A

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  42. J

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  43. king yasin ally

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  44. berkeman

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    I saw this antenna matrix on the north coast of California this week on vacation (a couple miles north of Half Moon Bay). It's located about 1/4 mile from the beach on Highway 1. There is a powerline running past it, but it looks to just be getting much of its power from a trickle charge from...
  45. baby_1

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  46. S

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    As any RF engineer knows the radial antenna is something pure theoretical. But as someone who loves physics an idea came to my mind. Please tell me if this would work and if not, why does it fail to work. So: Assuming we have an atom with 8 valence electrons which is hit with 8 photons with...
  47. B

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  48. I

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  49. S

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  50. T

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