Array antenna is a set of two or more antennas. The signals from the antennas are combined or processed in order to achieve improved performance over that of a single antenna.
For theory see:
Orphanids, S: Electromagnetic Waves and Antennas, 2004-10, chapter 14: http://www.ece.rutgers.edu/~orfanidi/ewa/ch20.pdf
Kraus, J.D., Marhefka, R.J.: Antennas for all applications, Mc Graw Hill 2003, chapter: Arrays of point sources I and II (5)
Simulations - 4 dipole array:
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An example of 4 dipole array, distributed along y-axis. |
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The separation between dipoles is λ/4 and they are fed with the same amplitude and phase. In this case the radiation is "broadside" with maximum perpendicular to the array axis. |
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The same as above but now the phasing is (from dipole 1 to 4): 0, 20, 40, 60 degrees. The beam is now tilted. |
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The same as above but now the phasing is (from dipole 1 to 4): 0, 50, 100, 150 degrees. The beam is tilted more and is also broaden. |
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The separation between dipoles is λ/2 and they are fed with the same amplitude and opposing phases (0,180,0,180 degrees). This setup leads to so-called "end-fire" radiation, i.e. the main beam is now aligned with the array axis y. |
Gallery:
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