Three-dimensional antenna radiation patterns. The radial distance from the origin in any direction represents the strength of radiation emitted in that direction. The top shows the directive pattern of a horn antenna, the bottom shows the omnidirectional pattern of a simple vertical dipole antenna.
In the field of antenna design the term radiation pattern (or antenna pattern or far-field pattern) refers to the directional (angular) dependence of the strength of the radio waves from the antenna or other source.[1][2][3]
Particularly in the fields of fiber optics, lasers, and integrated optics, the term radiation pattern may also be used as a synonym for the near-field pattern or Fresnel pattern.[4] This refers to the positional dependence of the electromagnetic field in the near field, or Fresnel region of the source. The near-field pattern is most commonly defined over a plane placed in front of the source, or over a cylindrical or spherical surface enclosing it.[1][4]
The far-field pattern of an antenna may be determined experimentally at an antenna range, or alternatively, the near-field pattern may be found using a near-field scanner, and the radiation pattern deduced from it by computation.[1] The far-field radiation pattern can also be calculated from the antenna shape by computer programs such as NEC. Other software, like HFSS can also compute the near field.
The far field radiation pattern may be represented graphically as a plot of one of a number of related variables, including; the field strength at a constant (large) radius (an amplitude pattern or field pattern), the power per unit solid angle (power pattern) and the directive gain. Very often, only the relative amplitude is plotted, normalized either to the amplitude on the antenna boresight, or to the total radiated power. The plotted quantity may be shown on a linear scale, or in dB. The plot is typically represented as a three-dimensional graph (as at right), or as separate graphs in the vertical plane and horizontal plane. This is often known as a polar diagram.
^ abcConstantine A. Balanis: “Antenna Theory, Analysis and Design”, John Wiley & Sons, Inc., 2nd ed. 1982 ISBN 0-471-59268-4
^David K Cheng: “Field and Wave Electromagnetics”, Addison-Wesley Publishing Company Inc., Edition 2, 1998. ISBN 0-201-52820-7
^Edward C. Jordan & Keith G. Balmain; “Electromagnetic Waves and Radiating Systems” (2nd ed. 1968) Prentice-Hall. ISBN 81-203-0054-8
^ abInstitute of Electrical and Electronics Engineers, “The IEEE standard dictionary of electrical and electronics terms”; 6th ed. New York, N.Y., Institute of Electrical and Electronics Engineers, c1997. IEEE Std 100-1996. ISBN 1-55937-833-6 [ed. Standards Coordinating Committee 10, Terms and Definitions; Jane Radatz, (chair)]
In the field of antenna design the term radiationpattern (or antenna pattern or far-field pattern) refers to the directional (angular) dependence of the...
The radiation-field pattern can be calculated by applying Huygens' principle in a similar way to a rectangular aperture. The electric field pattern can...
half of the dipole, which adds to the direct radiation to form a dipole radiationpattern. So the pattern of a monopole with a perfectly conducting, infinite...
needed] The dipole is any one of a class of antennas producing a radiationpattern approximating that of an elementary electric dipole with a radiating...
in the medium. Also known as the radiation-zone, the far field carries a relatively uniform wave pattern. The radiation zone is important because far fields...
field radiationpattern of an antenna or other radiation source, that are not the main lobe. The radiationpattern of most antennas shows a pattern of "lobes"...
and reception.[citation needed] Large loop antennas have a two-lobe radiationpattern at their first, full-wave resonance, peaking in both directions perpendicular...
monopole antenna, and like a vertical dipole has an omnidirectional radiationpattern, radiating equal radio power in all azimuthal directions (perpendicular...
zero on the axis. When graphed in three dimensions (see graph) this radiationpattern is often described as doughnut-shaped. This is different from an isotropic...
center. The pattern of electric and magnetic fields at the aperture plane at the mouth of the horn, which determines the radiationpattern, is a scaled-up...
5 m). The radiationpattern of a thin wire antenna is easily predictable using antenna modeling. For a straight wire, the radiationpattern can be described...
that is dynamically adjusted, typically the frequency of operation, radiationpattern or polarization. Frequency reconfigurable antennas can adjust their...
the radiationpattern containing the highest power or exhibiting the greatest field strength. The radiationpattern of most antennas shows a pattern of...
array antennas in which the phase of the feed power and thus the radiationpattern of the antenna array is fixed. For example, AM broadcast radio antennas...
absorbing and reradiating radio waves from the mast, disturbing the radiationpattern of the antenna. To prevent this, additional strain insulators are...
Radiation resistance is that part of an antenna's feedpoint electrical resistance caused by the emission of radio waves from the antenna. A radio transmitter...
electromagnetically with the driven element, and serve to modify the radiationpattern of the antenna, directing the radio waves in one direction, increasing...
accuracy is also difficult to determine. Other radiation efficiency measurement techniques include: the pattern integration method, which requires gain measurements...
wave vertical and the radiationpattern,[citation needed] similar to these antennas is omnidirectional, with maximum radiation at right angles to the...
steering is a technique for changing the direction of the main lobe of a radiationpattern. In radio and radar systems, beam steering may be accomplished by...
coordinates (X,Y,Z) is for the probe radiationpattern to be as close as possible to ideal short dipole pattern, called sin θ: f ( θ , ϕ ) = A sin (...
"main lobe") of its radiationpattern. This apparent power is dependent on two factors: the total power output and the radiationpattern of the antenna –...
unit cell is minimised, an aperture area appropriate to the feed radiationpattern can efficiently focus the wavefronts from the feed. Transmitarrays...
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