The difference between omnidirectional antenna and directional antenna
Antennas have different radiation or receiving capabilities in different directions in space, which is the directivity of the antenna. Depending on the directivity, there are two types of antennas: omnidirectional and directional. The following mainly explains the differences between them and related parameters.
An omnidirectional antenna, that is, shows uniform radiation at 360° on the horizontal pattern, which is commonly referred to as non-directional. In general, the smaller the lobe width, the greater the gain. Omnidirectional antennas are generally used in communication systems with short distances, large coverage areas and low prices. The figure below shows the signal radiation pattern of an omnidirectional antenna.
Directional antennas show a certain angular range of radiation on the horizontal pattern, which is called directional. Like the omnidirectional antenna, the smaller the lobe width, the greater the gain. Directional antennas are generally used in communication systems where the communication distance is long, the coverage area is small, the target density is high, and the frequency utilization rate is high. The figure below shows the signal radiation pattern of a directional antenna.
Relationship between omnidirectional antenna and directional antenna
We can think about the relationship between an omnidirectional antenna and a directional antenna like this: the omnidirectional antenna emits signals in all directions, and the signals can be received from the front, back, left, and right. The directional antenna is like a strong reflecting surface behind the antenna. It can only be transmitted to the front, and the signal to the back is blocked by the reflective surface and reflected to the front, which strengthens the signal strength in the front.
How to choose the antenna
If you need to meet multiple sites and these sites are distributed in different directions of the AP, you need to use omnidirectional antennas; if they are concentrated in one direction, it is recommended to use directional antennas; in addition, consider whether the antenna joint form matches the AP and the antenna Whether the size of the gain meets your needs.
Omni Directional Antenna -- Rubber Antenna, PCB Antenna, Fiberglass Antenna, Magnetic Antenna...
Directional Antenna -- Panel Antenna, Yagi Antenna...
For outdoor antennas, lightning protection equipment needs to be added between the antenna and the wireless AP; for directional antennas, pay attention to the direction that the front of the antenna faces the remote site; the antenna should be installed as high as possible, and the line of sight between the antenna and the site should be as high as possible (Visible to the naked eye, avoid obstacles in the middle).
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