Dipole antennas, also known as dipole aerials, doublets, or wire antennas, are a type of simple radio frequency antenna that can receive and broadcast at the same time. Due to their omnidirectional signal coverage, these are widely used in a variety of technologies and as components of more complex antennas. When radio frequency current passes through them, electromagnetic or radio signals are produced. Dipole antennas, like wire antennas, can be found in a variety of places, including cars, televisions, AM-FM radios, and wireless routers.
Dipole antennas were invented in 1886 by Heinrich Rudolph Hertz and serve as the backbone for radio frequency broadcasts. The term dipole refers to the fact that these antennas are made up of either a single straight rod or two equal-length rods, also known as conductors. This is then connected to the center point of a radio feed line. The antenna’s two poles, or dipoles, are formed by this split.
The antenna’s length should be half its wavelength. To put it another way, dipole antennas are most effective when they operate at a frequency with a wavelength twice the antenna’s overall length. Depending on the device’s intended use, other variants may include three or five wavelengths.
The polarization of dipole antennas changes with their positions, whether they are oriented vertically, horizontally, or at an angle. Depending on the polarization and how they align with the antenna position, this may change how receptive they are to frequencies. When adjusting traditional rabbit ear antennas to improve television picture quality, for example, the changes in antenna position actually change how the antennas align with the broadcast signal to improve overall reception. When adjusting the length or position of a car antenna to improve radio reception, the same thing happens.
The RF current and RF voltage are the two elements that make up the antenna frequency. The strength of these elements is inversely proportional to their location along the antenna’s length. It’s useful to remember that the RF current’s amplitude is highest in the middle and lowest at the ends. The RF voltage, on the other hand, is weakest in the middle and strongest at the poles.
Combining the basic antenna with more sophisticated deflector or reflector components, which can improve gain and directivity, can improve the function of dipole antennas. This improves the overall signal, allowing the antenna to receive or broadcast more information and extend its range. This method is especially useful in the broadcasting of wireless signals, such as in wireless access points.