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What is the radiation pattern of folded dipole antenna?
The radiation pattern of half-wave folded dipoles is the same as that of the half-wave dipole antennas. Half-wave folded dipole antennas are used where optimum power transfer is needed and where large impedances are needed. This folded dipole is the main element in Yagi-Uda antenna.
What is the difference between linear dipole and folded dipole?
The physical difference is that the folded dipole is comprised of a dipole with a second parallel conductor connected at its ends, to the ends of the dipole. Folded dipole antennas and their subsequent designs have a wide variety of advantages in both bandwith and impedance.
When to use a half wavelength folded dipole antenna?
Hence, the half-wavelength folded dipole antenna is often used when larger antenna impedances (>100 Ohms) are needed. The radiation pattern of half-wavelength folded dipoles have the same form as that of half-wavelength dipoles .
How does the impedance of a folded dipole work?
Also, because the folded dipole is “folded” back on itself, the currents can reinforce each other instead of cancelling each other out, so the input impedance will also depend on the impedance of a dipole antenna of length L.
Why is the radiation pattern of a dipole important?
The radiation pattern of a dipole antenna is of particular importance for many reasons it needs to be orientated so that it picks up the maximum level of signal or radiates the maximum amount of signal in the required direction. The radiation pattern reflects the amount of power radiated from the dipole in any given direction.
How are dipoles used in the FM band?
Another common place one can see dipoles is as antennas for the FM band; these are folded dipoles. The tips of the antenna are folded back until they almost meet at the feedpoint, such that the antenna comprises one entire wavelength. This arrangement has a greater bandwidth than a standard half-wave dipole.