What is the feed impedance of folded dipole antenna?

What is the feed impedance of folded dipole antenna?

On their own: Folded dipole antennas are sometimes used on their own, but they must be fed with a high impedance feeder, typically 300 ohms. This on its own can be very useful in certain applications where balanced feeders may be used.

How do you feed a dipole?

Feeding a dipole antenna. Ideally, a half-wave dipole should be fed using a balanced transmission line matching its typical 65–70 Ω input impedance.

What does a folded dipole antenna look like?

A folded dipole is an antenna, with two conductors connected on both sides, and folded to form a cylindrical closed shape, to which feed is given at the center. The length of the dipole is half of the wavelength. Hence, it is called as half wave folded dipole antenna.

What is the feed impedance of a folded dipole antenna?

If the diameter of the main conductor and the folded dipole are same, then there will be four folded (two times of squared one) increase in the feed impedance of the antenna. This increase in feed impedance is the main reason for the popular usage of this folded dipole antenna. Due of the twin-lead, the impedance will be around 300Ω.

How is coax fed to a folded dipole?

The coax is hidden entirely inside the pipe, so it has the minimum effect on the patterns, and no balun is required to feed the balanced antenna from the unbalanced input. The coax should see the full 200-300 ohm impedance of the folded dipole, so a bad match without further work.

Why do we use half wave folded dipoles?

This increase in feed impedance is the main reason for the popular usage of this folded dipole antenna. Due of the twin-lead, the impedance will be around 300Ω. The radiation pattern of half-wave folded dipoles is the same as that of the half-wave dipole antennas.

How is the length of a folded dipole determined?

A folded dipole is an antenna, with two conductors connected on both sides, and folded to form a cylindrical closed shape, to which feed is given at the center. The length of the dipole is half of the wavelength.