Antenna Theory End-fire Array - Antenna Theory

What is Antenna Theory End-fire Array?

The physical arrangement of end-fire array is similar as that of the broad side array. The magnitude of currents in each element is same, but there is a phase variance amongst these currents. This induction of energy varies in each element, which can be implicit by the resulting diagram.

end_fire_array

The beyond figure illustrates the end-fire array in top and side views correspondingly.

There is no radiation in the right angles to the plane of the array because of cancellation. The first and third elements are fed out of phase and so cancel each other’s radiation. Likewise, second and fourth are fed out of phase, to get cancelled.

The normal dipole spacing will be λ/4 or 3λ/4. This planning not only helps to evade the radiation perpendicular to the antenna plane, but also helps the radiated energy get distracted to the direction of radiation of the whole array. Therefore, the minor lobes are evaded and the directivity is improved. The beam develops narrower with the increased elements.

Radiation Pattern

The Radiation pattern of end-fire array is uni-directional. A main lobe happens at one end; where supreme radiation is exist, while the minor lobes represent the losses.
end_fire_radiation

The figure clarifies the radiation pattern of an end-fire array. Figure 1 is the radiation pattern for a single array, while figures 2, 3, and 4 signify the radiation pattern for multiple arrays.

End-fire Array Vs Broad Side Array

We have considered both the arrays. Let us try to associate the end-fire and broad side arrays, along with their features.
end_fire_broad_side

The figure shows the radiation pattern of end-fire array and broad side array.

  • Mutually, the end fire array and broad side array are linear and are resonant, as they contain of resonant elements.
  • Due to resonance, both the arrays show narrower beam and high directivity.
  • Both of these arrays are used in transmission purposes.
  • Neither of them is used for reception, because the need of covering a range of frequencies is needed for any kind of reception.

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