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. T

    Microstrip Antenna: What is Low Profile?

    I found in many sources describing microstrip antennas are 'low profile'. Well, I know several antenna parameters like radiation pattern, antenna gain, intensity, directivity etc. But what is this 'low profile'?? Can anyone tell me what sort of property of an antenna does the term 'low profile'...
  2. Seanskahn

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  3. K

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  4. D

    Antenna Design Books: 60Hz to 100KHz Textbooks/Ref Material

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  5. B

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  6. F

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  7. C

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  8. D

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  9. D

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  10. H

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  11. J

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  12. L

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  13. S

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  14. W

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  15. L

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  16. W

    Antenna Polarization: Fixed E-field Orientation?

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  17. E

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  18. M

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  19. S

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  20. S

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  21. C

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  22. P

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  23. A

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  24. I

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  25. Y

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  26. S

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  27. S

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  28. A

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  29. M

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  30. W

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  31. W

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  32. H_man

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  33. C

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  34. M

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  35. H

    How does current flow in an antenna?

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  36. J

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  37. O

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  38. C

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  39. D

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  40. O

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  41. O

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  42. E

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  43. K

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  44. P

    Creating visible light using an antenna

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  45. C

    Omni-directional Antenna Questions

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  46. T

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  47. W

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  48. W

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  49. X

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  50. J

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