Dipole Antenna Length Calculator

Dipole Antenna

A dipole antenna consists of two conductive rods or metals of equal lengths separated by an insulator. It is one of the simplest types of antennas and has a 360-degree radiation pattern. The rods are connected to a wire also called a feeder at the end closest to the center of the antenna. The total length of the rods is usually one-half of the maximum wavelength of the signals.

When the current is fed to the rods from the feeder the current becomes negligible because the electrons have nowhere to move beyond the end of the rods. Similarly, the RMS current reaches its maximum level in the center of the rods. This leads to the potential difference, thus having maximum RMS voltage towards the end of the rods and minimum at the center.  So, when the current flows through the dipole, it is negatively charged on one side and rises to its maximum charge. During the next half-cycle of the current supplied this negatively charged dipole side becomes zero and then positively charged. This process of charging from negative to positive of the dipoles results in the rising and falling of the electric field moving away from the antenna. The current also creates a magnetic field that moves away from the antenna. This results in the radiation of electromagnetic waves. 

Length of the Dipole

The length of the dipole is usually one-half of the wavelength of the RF signals. The length of a half-wavelength dipole can be calculated by the given formula:

L =  

 Where L is the length of the dipoles 

             f if the frequency of the RF signals.

“468” is the constant used to convert frequency in MHz to feet.