Why does the em field exist predominantly magnetic or electric in the near field region?
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What's The Difference Between EMNear Field And Far Field? ... As it turns out, an electromagnetic field'scharacteristics change depending on the distance from the antenna. This varying field is typically divided into two segments—the near field and thefar field
The near field and far field are regions of the electromagnetic field (EM) around an object, such as a transmitting antenna, or the result of radiation scattering off an object. Non-radiative 'near-field' behaviours of electromagnetic fields dominate close to the antenna or scattering object, while electromagnetic radiation 'far-field' behaviours dominate at greater distances.
Far-field E (electric) and B (magnetic) field strength decreases inversely with distance from the source, resulting in an inverse-square law for the radiated power intensity of electromagnetic radiation. By contrast, near-field E and B strength decrease more rapidly with distance: part decreases by the inverse-distance squared, the other part by an inverse cubed law, resulting in a diminished power in the parts of the electric field by an inverse fourth-power and sixth-power, respectively. The rapid drop in power contained in the near-field ensures that effects due to the near-field essentially vanish a few wavelengths away from the radiating part of the antenna
The near field and far field are regions of the electromagnetic field (EM) around an object, such as a transmitting antenna, or the result of radiation scattering off an object. Non-radiative 'near-field' behaviours of electromagnetic fields dominate close to the antenna or scattering object, while electromagnetic radiation 'far-field' behaviours dominate at greater distances.
Far-field E (electric) and B (magnetic) field strength decreases inversely with distance from the source, resulting in an inverse-square law for the radiated power intensity of electromagnetic radiation. By contrast, near-field E and B strength decrease more rapidly with distance: part decreases by the inverse-distance squared, the other part by an inverse cubed law, resulting in a diminished power in the parts of the electric field by an inverse fourth-power and sixth-power, respectively. The rapid drop in power contained in the near-field ensures that effects due to the near-field essentially vanish a few wavelengths away from the radiating part of the antenna
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