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For a reciprocal antenna, these two patterns are identical. A multitude of antenna pattern measurement techniques have been developed. The first technique developed was the far-field range, where the antenna under test (AUT) is placed in the far-field of a range antenna.
Instead, the radiation pattern of the antenna is determined by a single simulation, and the receiving pattern inferred by reciprocity. When determining the pattern of an antenna by measurement, the antenna may be either receiving or transmitting, whichever is more convenient.
When actual measurements of an antenna's gain are made by a laboratory, the field strength of the test antenna is measured when supplied with, say, 1 watt of transmitter power, at a certain distance. That field strength is compared to the field strength found using a so-called reference antenna at the same distance receiving the same power in ...
In antenna engineering, sidelobes are the lobes (local maxima) of the far field radiation pattern of an antenna or other radiation source, that are not the main lobe.. The radiation pattern of most antennas shows a pattern of "lobes" at various angles, directions where the radiated signal strength reaches a maximum, separated by "nulls", angles at which the radiated signal strength falls to zero.
In electromagnetics, the antenna factor (AF, units: m −1, reciprocal meter) is defined as the ratio of the electric field E (units: V/m or μV/m) to the voltage V (units: V or μV) induced across the terminals of an antenna:
For such an antenna, the near field is the region within a radius r ≪ λ, while the far-field is the region for which r ≫ 2 λ. The transition zone is the region between r = λ and r = 2 λ . The length of the antenna, D, is not important, and the approximation is the same for all shorter antennas (sometimes idealized as so-called point ...
Radio propagation is the behavior of radio waves as they travel, or are propagated, from one point to another in vacuum, or into various parts of the atmosphere. [1]: 26‑1 As a form of electromagnetic radiation, like light waves, radio waves are affected by the phenomena of reflection, refraction, diffraction, absorption, polarization, and scattering. [2]
A reference antenna is an antenna with known performance. It is normally used to calibrate other systems. It is normally used to calibrate other systems. During a relative calibration, an antenna's phase center offset (PCO) and phase center variations (PCV) are computed with respect to the reference antenna which is normally assigned zero PCV ...