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For a typical k of about 0.95, the above formula for the corrected antenna length can be written, for a length in meters as 143 / f , or a length in feet as 468 / f where f is the frequency in megahertz.
The size of the induced dipole moment is equal to the product of the strength of the external field and the dipole polarizability of ρ. Dipole moment values can be obtained from measurement of the dielectric constant. Some typical gas phase values given with the unit debye are: [7] carbon dioxide: 0; carbon monoxide: 0.112 D; ozone: 0.53 D
Continuous charge distribution. The volume charge density ρ is the amount of charge per unit volume (cube), surface charge density σ is amount per unit surface area (circle) with outward unit normal n̂, d is the dipole moment between two point charges, the volume density of these is the polarization density P.
As the length of an antenna is made shorter than its fundamental resonant length (a half-wavelength for a dipole antenna and a quarter-wavelength for a monopole), the radiation resistance the antenna presents to the feedline decreases with the square of the electrical length, that is the ratio of physical length to wavelength, (/). As a result ...
The electric dipole moment is a measure of the separation of positive and negative electrical charges within a system: that is, a measure of the system's overall polarity. The SI unit for electric dipole moment is the coulomb-metre (C⋅m). The debye (D) is another unit of measurement used in atomic physics and chemistry.
As can be seen in the above table, for linear antennas shorter than their fundamental resonant length (shorter than 1 / 2 λ for a dipole antenna, 1 / 4 λ for a monopole) the radiation resistance decreases with the square of their length; [24] for loop antennas the change is even more extreme, with sub-resonant loops ...
The directivity of an actual antenna can vary from 1.76 dBi for a short dipole to as much as 50 dBi for ... Electrical length; ... From the above formula, ...
Antenna effective length = is the length which, multiplied by the electrical field of the received wave, give the voltage of the Thévenin equivalent antenna circuit. Maximum available power = G a λ 2 4 π Z ∘ E b 2 {\displaystyle =\displaystyle {{G_{a}\lambda ^{2} \over 4\pi Z_{\circ }}E_{b}^{2}}\,}