It’s a specialized antenna, often considered a hybrid of the dipole and loop antennas, or radiating elements.
Also called a helix antenna, it is a traveling wave antenna. It simply means that the current is traveling along the antenna while the phase is varying continuously.
What’s the helical antenna and its benefits?
A few of the benefits of the helix antenna is its wide bandwidth and real input impedance. This antenna is also constructed easily and is able to produce polarized fields. The two modes of polarization are namely, right-handed and left-handed helix antennas.
In the right-handed type, if you’re going to curl your right hand fingers around the antenna, the thumb would point up and the waves that will be emitted from the device are called “Right Hand Circularly Polarized.”
In the left-handed type, the thumb would point up if you would curl the left hand fingers around the antenna.
The conducting wire is wound in helix form in a helical antenna. In most cases, this antenna is mounted over a ground plane and with a feed line that is connected between the bottom of the helix and the ground plane.
And as it is a traveling wave antenna, the phase and the current changes continuously along it. For this reason, this antenna is popular for different applications. It is commonly used in applications like satellite and radio communications.
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The two modes supported are axial and normal. In the axial radiation mode, the radiation is in the axial direction, while its radiation is perpendicular to the axis in the normal radiation mode.
The helical antenna is an excellent circular polarization feed. It is also an ideal feed for a small offset dish if used in satellite applications. Those operating in the normal mode are used for a mobile radio and in broadcasting antennas. On the other hand, those running in axial mode are used for a satellite communication.
What are the uses of a helical antenna?
This antenna is used for applications that include transmission/reception of the VHF signals through the ionosphere, radiometry or satellite applications and it’s possible to establish the communication between the moon and the earth.
What are the pros of using a helical antenna?
It has a simple design and is acceptable by vertical/horizontal polarized types of antennas because of its circular polarized pattern.
The antenna can also be used for broadband applications as it has a wide bandwidth. In addition, it can be used at VHF or HF frequencies for transmission and reception. More so, it can offer a higher directivity and has a durable construction.
But if there are upsides, there are downsides, too. For one, it is bulky and large in size. It also needs an extra space for installation.
You also have to know that its efficiency can decrease with a higher number of turns.
Remember that its max efficiency of around 80% is achievable by using between three to four turns. This antenna is also a costly antenna.
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