What is Antennas: Definition and 96 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. bob012345

    Simulation of two Small Interacting Antennas

    I would like to simulate two small interacting antenna's with fields and forces in 3D. They can be simple wire antenna. I am asking if there is a recommendation for software that can reasonably accurately handle that which is free? Thanks.
  2. DC2

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  3. B

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  4. A

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  5. Johan L

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  6. P

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  7. tworitdash

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  8. P

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  9. shushi

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  10. M

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  11. M

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  12. M

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  13. P

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  14. V

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  15. alan123hk

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  16. T

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  17. S

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  18. D

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  19. davenn

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  20. J

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  21. T

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  22. M

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  23. J

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  24. M

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  25. qnach

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  26. P

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  27. M

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  28. P

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  29. Newtons Apple

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  31. berkeman

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  32. Anton Alice

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  33. R

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  34. Tyatyra

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  35. A

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  36. U

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  37. P

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  38. R

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  39. L

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  40. Averagesupernova

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  41. S

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  42. J

    Coupled Antennas: Literature on Small Separation Distances

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  43. R

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  44. M

    How do radio antennas convert electrical energy into photon energy?

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  45. U

    Two interfering antennas with single photon radiation

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  46. S

    Radio Antennas and Young's Double slit

    Homework Statement Two radio antennas separated by d = 294 m as shown in the figure below simultaneously broadcast identical signals at the same wavelength. A car travels due north along a straight line at position x = 1 290 m from the center point between the antennas, and its radio...
  47. I

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  48. N

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  49. D

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  50. harts

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